Well, an update. I have been able to find some roundballs at .672, and using 18 gr. Unique with a roll crimp, these seem to give decent accuracy, and more or less regulate. I will be receiving a fosbery style mould soon, and will try that. Just loaded up 10 of the balls, and shot at steel at 100 m, so can't really speak for the accuracy, but they will hit a 12x 18 plate at that range. Now I need to find a ball mould at that diameter!
Doug