Hello everyone!

I have a question (or two) for those of you more experienced with casting, since I have never had any done before.

Background is; I am making wedding and engagement rings for me and my girlfriend, so naturally I don't want to mess up too badly.
Since we are both not too fond of golden things I thought I'd have it cast in Palladium. So naturally I need to get it cast at a professional caster since I don't have the equipment to solder or cast it at home.

The rings themselves I will design using CAD, then let the caster print and cast it. (I have no experience of working with wax either, plus, it saves shipping costs). Since I know our measurements in mm it is also easy to adjust it in CAD.

According to a caster I spoke to there would be almost no shrinkage due to wax model and casting in Palladium, so that is good.

Now for the actual questions:

1) I will be using a court shaped ring (shallow curved on the inside) for all rings since it is more comfortable. However, my question is how this affects measurements. Since fingers are quite soft I would guess that the measurement would be using the maximum inner diameter more than the minimum inner diameter, since that is what will be pressed against the finger and it will become too loose if only using the minimum diameter.
So, would I make the rings a little bit smaller to match the maximum inner diameter, use the minimum or somewhere in between?

2) Finishing. I have seen a bit of reference that you will lose a bit of material to finish up a cast. The question is, how rough do they usually come out, how much do I need to polish away, and will it affect the size to a degree that I need to adjust for it?

I know I can make it a little bit smaller and then size it up a bit, but I don't want to make it too small or too big to begin with since it is the first time casting, and it will be a fairly expensive one at that.

Do anyone have any (other) advice?

/Andreas