Thanks for the info.
What I was looking for was someone who'd been successful at a heavy cast non-GC bullet.
(I have a Rem 700 in 35 Whelen with 1:16 twist - some folks get the 1:16 to work with the 358009 bullet some don't - mine didn't.)
Similar situation here, need to find someone who's DONE it and to see how heavy it's been done successfully. I've found emperically now that 340 gr is a bit much. Since moulds aren't cheap, I'd like to know which ones work in practice.