I'm saying he should be checking the deck height with the base gasket in place. As for the reference to the degree wheel, I was just clarifying the reason some guys use a wheel when coming up with the numbers for domes. Obviously I only gave the most general reason which would be finding absolute TDC. However, if the motor is ported it would help an experienced builder to know when the ports are opening and closing to know the actual trapped volume that will be compressed/ignited. That way they can spec the proper sized dome. Guess I should of added that in my first post.
But if you already have the motor assembled, just throw a L sheped piece of solder in there and figure out what it is and make your changes from that measurement.