Blue soft is your best choice, going on easier and staying better than any lube I know of, whether with fingers or lubrisizer. It flows nicely through any sizer without heat.
When you buy an LBT mold you are paying for a custom diameter, so I strongly encourage you to measure your gun. 431 will shoot well in almost any revolver out there, unsized, if seated deep enough so the forward driving band doesn't hang up in the throats, but if your gun happens to need a larger bullet, you'll sacrifice accuracy and have to play with powder charges a bit to find a pressure with bumps the base up to get a seal befor the bullets starts moving.
When shooting unsized LBT bullets, most will require seating deeper than the crimp to get them to chamber easily, if they are large enough in diameter to allow sizing to a perfect cylinder throat fit, as is required for optimum accuracy and power potential. For this reason, I reccomend a 280 or even 260 gr WFN, and plain based for hand lubing, because gas checks which aren't sized will expand the brass when seated destroying the necessary case neck grip to hold bullets from crawling out under recoil. A 260 gr will anchor most decently hit deer, elk, and smaller game in their tracks with starting velocities as low as 1200 fps, with hits out to 150 yards. You don't need 300 gr to do the job. If you already had a sizer I'd reccomend a 280 gr WFN first, or 300 gr, and the WLN if 320 gr or heavier was wanted.
