I can not honestly answer the head milling question. I had a stock head milled .020 and had the domes cut to act as "drop down" domes, so the domes were further down into the cylinder as you can buy them from TBM and I believe JSU as well...and maybe some others. I forget what spec exactly my domes were "dropped," and I no longer own the head.
If you are looking at buying an aftermarket head, I'd say go for the TBM limited setup, with the drop down domes and universal head cap. The universal head cap allows the fit of either the Factory Pipe Dry Pipe or TBM's own twin pipes. If you are not running an aftermarket pipe I would still get the universal head cap incase you ever want to sell it...it will make it more appealing to others who may have one of those two pipe options. A girdle kit when running a dry pipe is also necessary to prevent cylinder cracking. I even recommend it for a wet pipe but that is just my opinion, I like to be on the safe side, and once again it would be more appealing to all if I chose to sell it.
I believe TBM recommends 26cc domes for their limited setup, however you can run whatever you'd like, depending on how crazy you want to get or what octane gas you would like to run.
That is just my personal opinion on how I would set up my own ski if I was building what you are looking for. I would, however, not buy a TBM head as I have my own custom made one's for my Limited race ski, and I have a few extras. Nothing wrong with TBM at all, but I wouldn't spend the cash since I already have my custom heads, that is all. For you, TBM is the way to go IMO. Tim Bushman is also a great guy and has great advice and is very knowledgeable, speak with him about your setup and he can probably set you up beautifully.
Hope that helps,
Luke