You kind of have me there.
Every cc will drop or raise it about .10, so about 10 cc for a full point. How much off the surface 1 cc is I do not know. I am guessing quite a bit.
I would think that it would be easier to polish the chambers adding head cc to get the 410 compression down, than it would be to raise the 390 compression. If the clearances stack up right, you might even end up in the usable range without any work. In addition, the cam might help you out, even at 10.0 or so a more radical cam would get the DCR down due to the intake closing time.
Speed Pro/Federal Mogul makes a standard 390 piston that gives more reasonable compression in a 390, so selling those to someone who wants to make a 410 might be an option.
You could search the FE Forum on network 54, and/or ask there. Many there know ALOT more than me.
http://www.network54.com/Forum/74182
I was going to build a 410, which is why I have these three pistons, after studying them I decided to go with the forged 390 ones, so quit messing with the others.