Whats the least amount of bearing surface in the neck I can get away with.
I only use this rifle for target matches.
I don't know. A lot would be how careful you are handling them and feeding them into the chamber.
A lot of people are shooting 185s in FT/R. You might consider them if you can't get the Fullbores to jump well.
As Broz said, many of us have shot factory chambered Weatherby's for years and jumped all kinds of bullets but the short bearing surface ones don't always come out of the barrel with competition required accuracy. I used to shoot some 115 HPs in a 7mm Wby at ridiculous speeds and moderate accuracy at groundhogs but I seldom killed any over 350yds away with that combination.