You're welcome. I think it would've probably been balanced around two L4 PC's, as you found three L4 PC's plus the L5 drake were a bit much for the L3 solo (L3 solo = 4 L3 characters) .. as you discovered, two L3 solos were a bit much for that party. Three L3 PC's plus the L5 Drake might have been a better match for the one dragon.
The one chunk of feedback I'd give would be "don't deny the players their victory"; in this example, your PC's had the dragon beaten, and he brought in another one, which led to them giving up .. that denies the player the "thrill of victory". Its okay for the PC's to lose every now and then
but, primarily, its the DM's job to set up what look like impossible odds, but actually aren't, and then to lose gracefully to the players.
The worst two examples of this I've seen in actual play were:
1. Final battle of the adventure, PC's interrupt a summoning ritual: the bad guys are bringing some otherworldly creature through a gate! PC's have a McGuffin which can shut the gate. PC's are outnumbered and shouldn't be able to win in a straight fight .. or at least, not in time to stop the ritual. PC's get some lucky, heroic rolls, and wind up on the verge of stopping the ritual .. at which point an evil priest grabs the McGuffin from the wizard, and leaps through the gate to the other side.
The ritual was stopped and the party got to mop up the priest's remaining henchmen .. but it denied the PC's their very satisfying resolution to the battle. Especially egregious as the priest wasn't a named BBEG whom we might expect to see as a recurring character, the McGuffin did nothing for him, and the gate closed when he jumped through leaving us no way to chase him .. at that point it just felt "cheap", especially when the DM never did bring us back to a point where we could fight the priest, regain the McGuffin, or anything, so it wasn't even "justified by story".
2. Not that "story" justifies a "railroad" either: Solo adventure, paladin finds evil priest sawing off the horn of a living unicorn, protected by a dozen henchmen, monsters, etc. Paladin gets amazingly lucky with multiple critical hits plus multiple fumbles by the henchmen, and hacks her way to him well before the DM expected it. DM has the priest keep sawing at the horn, and rules that that doesn't even trigger an opportunity attack for the adjacent paladin, even though the priest makes no effort to defend himself from the paladin. Paladin hacks away at him, but he completes his ritual before turning (far too late) to fight the paladin, and dies, severed horn in his hand.
It was pretty clear that the DM had his "script" firmly in mind: "paladin is too late, and the priest saws off the horn!" .. rather than intending for the paladin to ever have a chance of rescuing the unicorn before it lost its horn. At the end of the battle, rather than feeling the satisfaction of having killed the priest, the player felt failure for failing to rescue the unicorn plus resentment that the DM's rulings and suicidal tactical choices had made it impossible even with all the 1's and 20's that had been rolled in what really looked like "divine intervention" in play at the table!
. . .
Not criticising, its just something to keep in mind for the future, especially if you have players who are participating in a multi-session adventure path or campaign.
Glad you guys had fun today!
The one chunk of feedback I'd give would be "don't deny the players their victory"; in this example, your PC's had the dragon beaten, and he brought in another one, which led to them giving up .. that denies the player the "thrill of victory". Its okay for the PC's to lose every now and then

The worst two examples of this I've seen in actual play were:
1. Final battle of the adventure, PC's interrupt a summoning ritual: the bad guys are bringing some otherworldly creature through a gate! PC's have a McGuffin which can shut the gate. PC's are outnumbered and shouldn't be able to win in a straight fight .. or at least, not in time to stop the ritual. PC's get some lucky, heroic rolls, and wind up on the verge of stopping the ritual .. at which point an evil priest grabs the McGuffin from the wizard, and leaps through the gate to the other side.
The ritual was stopped and the party got to mop up the priest's remaining henchmen .. but it denied the PC's their very satisfying resolution to the battle. Especially egregious as the priest wasn't a named BBEG whom we might expect to see as a recurring character, the McGuffin did nothing for him, and the gate closed when he jumped through leaving us no way to chase him .. at that point it just felt "cheap", especially when the DM never did bring us back to a point where we could fight the priest, regain the McGuffin, or anything, so it wasn't even "justified by story".
2. Not that "story" justifies a "railroad" either: Solo adventure, paladin finds evil priest sawing off the horn of a living unicorn, protected by a dozen henchmen, monsters, etc. Paladin gets amazingly lucky with multiple critical hits plus multiple fumbles by the henchmen, and hacks her way to him well before the DM expected it. DM has the priest keep sawing at the horn, and rules that that doesn't even trigger an opportunity attack for the adjacent paladin, even though the priest makes no effort to defend himself from the paladin. Paladin hacks away at him, but he completes his ritual before turning (far too late) to fight the paladin, and dies, severed horn in his hand.
It was pretty clear that the DM had his "script" firmly in mind: "paladin is too late, and the priest saws off the horn!" .. rather than intending for the paladin to ever have a chance of rescuing the unicorn before it lost its horn. At the end of the battle, rather than feeling the satisfaction of having killed the priest, the player felt failure for failing to rescue the unicorn plus resentment that the DM's rulings and suicidal tactical choices had made it impossible even with all the 1's and 20's that had been rolled in what really looked like "divine intervention" in play at the table!
. . .
Not criticising, its just something to keep in mind for the future, especially if you have players who are participating in a multi-session adventure path or campaign.
Glad you guys had fun today!