I use the 358156 and the Lee 158 gcswc from my GP100. Both cast from range scrap sized .358 and using BLL. I used to use a stiff charge of 2400 but have recently switched to ACC#9, they run just as fast but the recoil feels less "snappy" to me.
The Lee boolit is just a shade more accurate for me at 50yds, but I shoot more of the old Lyman just because I like it!