It doesn't have to be complicated or overly houseruley. If the length of the SR is the issue, make it 5 minutes, or even instantaneous, and just hand it out every 2 or 3 encounters (assuming a 6-8 encounter day). The 5 minute recharge isn't hard to manage and it won't detract from the flow of the game. Narrate it in as part of the encounter - it happens at the end of a breakpoint encounter (i.e. 2 and 4 for a 6 encounter day). The last Orc sides to the ground, dead. You pause for a moment to catch your breath and take stock of the party's supplies and condition. That last bit is DM code for recharge your SR abilities, and is set up with the players before hand. No break in narration, no pause in action, no looking around for a place to rest. Just reset and go, the players can manage their character sheet while they loot the bodies or whatever. The classes stay balanced, no real rule hacking needed to be done. Nice and simple. It does leave the decision making in the hands of the DM and not the players, but I'm ok with that as it helps deal with the 5 minute workday issue some campaigns seem to have.