Hiya CFwase.

Give them a ring, tell em whether it's for street or race (it'll affect the amount they machine outa them, and the width of the rings) and the bore size you want to run.
If you're using stock rods and crank they'll probably know the pin height. If you want flat tops it's pretty easy, you'll just need to figure out whether you'll need valve cutouts or not. Might pay to get them to leave a bit of meat in the crown if you need cutouts.
I've done my own valve cutouts by making a cutter out of a sacrificial valve, doing a mock assembly with an old head, and spinning the valve on the end of a drill to cut the relief out. You can put a line or hose clip on the valve stem to ensure you dont go too deep.