Dan,
John VM summed it up pretty good!
There are few fellers in Scandinavia using your 68 FBs in national & intl. level and are doing pretty good with em'. Personally i've shot only Bart's 65 BTs which were made to .790" J4 jackets. Don't know the situation nowadays. In the beginning i didn't have any reference for bullets. At the time i looked statistics and decided to order BTs which seemed to be in the top of the equipment lists. I tried the FBs also, but find BTs seats smoother as stated earlier. Todays thin neck brass, N133 and hard neck tension + FBs aren't the best measuringwisely (if you measure the loaded cartridge). How much that effects in tight PPC chamber... Really don't know, you'll see the results on target i suppose. For 90% of competition shooters it's about personal believes, really don't think anyone have hard data between FBs or BTs.
Main thing is that you test, test, test your equipment, develope a well tuned load and you trust your equipment with a whole heart. Aggs are what we are shooting, not groups...
That's my 2 cent...
PS. Could there be a some kind of connection with fat BT bullets and growing .237" barrel bore diameter...