I shoot the TSX from my .300 WSM
and .223 as well as the TTSX from my .308. With the 45 grain TSX in the .223, I use a light collet crimp as well and it helps a lot. One thin that may help your accuracy is the TSX family seems to prefer .030 to .070 inch off the lands. Once you get your powder charge worked up while seated .050 off the lands, play with seeting depth in .010 increments to tune it in. My .223 is more service grade than accuracy so I was happy with 1 inch at 100 yards. My .308 and .300 WSM however shoot much tighter. It's fun showing TSX haters a 5 shot group tighter than a three shot group from their "super sweet handloads" lol. As for how to seet them, ignore the driving bands and seat to your rifles preference.