Tires: way bigger tires/rims, jeep club, air leak

Question
I'm an expert on the Suzuki portion of the site, and am asking for your "best guess" involving tires/rims.  I've got an 87 Samurai with a load of modifications, wrangler springs spoa, much lower t-case and diff ratios.  the question: previously I had Kumho 31x11.50s and now have Interco 34x9.50s on very offset 8" rims, and the tire mfg site gives specs for a 7" rim.  All the guys in the jeep club swear that when I air down to 13-15psi, I will unseat the bead, and just HAVE TO get beadlockers.  These are on a vehicle with a gross weight of 2900 and a functional fully loaded trail weight of just under 2500.  What's your best guess?  I really don't want to go to beadlocks with all the attendant cost and air leak issues.  I never had a problem before as long as I didn't drop below 10psi.  What's your best guess?  
David Scott

Answer
Scotty,

My best guess, huh?

I don't have much experience with off roading, so I am quite a bit out of my element.  I tend to think that experience is a better teacher.

But I don't think 13 to 15 psi is too low, provided there isn't a lot of sideways force put on the tire.