I would guess LA-2A's, 1176's and API 525's were probably used for compression on the records you are referring to. So you could try to stick to them for authenticity's sake. The smart/SSL, Sansamp and multiple multing thing are certainly very useful techniques (understandably so) for drum mixing but it's all a pretty 90's concept. Maybe going the simpler way might prove more in line with what you're trying to achieve.
I guess trying some serious squashing of that mono OH track to bring out the booth ambience could be an idea.
Also, use springs and plates if you need reverb. An EMT 250 on the shortest decay setting is good for a little space around/behind those acoustic guitars or dry drums, and a 140/145 is key for vocals. Tape slap back or live echo room could be fun too.
Just some ideas...
Good luck, sounds like a fun project to mix!

(Hopefully on an API or Neve series 80...heh )