.40 cal Keith nose molds

I've got a question for the casters/muzzleloaders here.

I am looking to have a die built to cast a 40cal Keith nose bullet with a slight boat tail to aid in loading with a sabbot in a 1-30 twist knight.

Should I go with straight wall or grooves? The straight will cast easier but may not size well.

What finish size would be best? .400 or the .401

What cast size will be best If I go with either style of bullet? .402 to .406

What will be a good finished weight of this projectile...wanting ballistics and kinetics to stay high out to 150+yds? 240-300gr

I will be casting very soft lead to slight antimony but still soft and drilling the tip using a fixture in a lathe to keep the weight consistent. I will be testing several cast bullets today to figure out the exact amount of drillings loss.

Any good places or leads to have the molds built? Right now I have the "Mountan Molds" in my sights but am open for suggestions.

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