Ry
Explorer
I'd pick a dragon around CR 12 to show off what those PCs can really take, but try to create a situation where the PCs have a few different avenues to gain info, do recon, or gain an advantage over the dragon.
I'd suggest having the dragon "trapped" in a cave complex - not in a single room mind you, the dragon can't get out the entrance but can stalk the players through the hive of caverns. That would make for a wicked fight. If you have the battle outside then I recommend having the PCs have a few avenues to bring the dragon to the ground.
Also, PREGENS are a must. MUST. Otherwise you won't be playing that day. 8th level + 5 feats takes a while to make.
I repeat: PREGENS ARE A MUST.
Cheers --ry
I'd suggest having the dragon "trapped" in a cave complex - not in a single room mind you, the dragon can't get out the entrance but can stalk the players through the hive of caverns. That would make for a wicked fight. If you have the battle outside then I recommend having the PCs have a few avenues to bring the dragon to the ground.
Also, PREGENS are a must. MUST. Otherwise you won't be playing that day. 8th level + 5 feats takes a while to make.
I repeat: PREGENS ARE A MUST.
Cheers --ry