Use a crappy omni for the talkback mic with a ton of compression. That way the 122dB guitar in between communications won’t be so loud. I learned that one from Mike Lastra at Smegmatone. You can also put this mic to tape as a sort of boombox sounding room mic or mix it in with a guitar solo to give it some space.
When mixing, send the snare through a gate and then some extreme compression, or better yet, a distortion unit (I use an Ibanez UE400 rackmount thing). Then bring it back in to a separate channel on the board so it doesn’t sound like a gated snare!
Try running tube mics direct to tape. No mic pre. Use a compressor if you need a little extra gain.
Disconnect your insert lines and just patch from tape to outboard gear to console. Less cabling = fewer headaches and better sound.
If you know you’re gonna have four or more guitars in the end, start cutting 2kHz on the guitar tracks as you overdub them so you don’t end up with an unusable mess of midrange.