I have 150# of alloy, its wheel weights with some plumbers tin, around 3% and according the fellow who made it the old wheel weights have 1% antimony. (he made this 11 years ago when WW's were better). So it isnt all that soft. I bought his whole rig including the pot, sizer/lube from Ideal and Lee moulds in .45ACP. I have been using his bullets which I got with the rig in .45 and the Colt is very clean.
I am now appraised to get the right slugging done. Except that this weekend I shoot with a bunch who use the same xd9's and they may know already what size the barrel is. They are reloaders.
Either way I am convinced that getting the right size is going to be worth the efforts.