I would mount the peep sight as close to your eye as you can. That would obviously be the REAR scope mounting holes, but you mention that may cause interference with the torch cam. If you must use the FRONT mounting holes, you may need to bore out the aperture some, as that is getting away from your eye a bit.

Anyway, mount it as close to your eye as you can without interfering with anything. I wouldn't worry too much about blowback. Just monitor and scrub when necessary. You won't have any problem with blowback using the front mounting holes.

I much prefer peep sights to regular iron sights, have used one for a long time on my T/C Renegade. Shot quite a few deer mostly within 50-75 yds.