Like Swage, I don't make pistol bullets either.
One thing I've noticed in bullet making is that the reduction in the length of a jacket after point forming is negligible.
What I would recommend is picking up some commercial bullets in the weights that interest you, and then simply using a caliper to measure the jacket length. This would (at least) give you a starting point. You could file one of these bullets in half, and then measure the jacket thickness. These numbers would give you the jacket length and thickness you want to order.
When you get some jackets on hand, you can weigh them, and use this number to establish how heavy your cores should be to make a bullet of the desired weight.
As Swage said, there's a lot of experimenting that goes on with this process, but you'll eventually come up with what you want.
