The dome should be shaped like the profile of WW1 helmets, not like the stock looking 13th century Mongol soup pot helmets, lol. If your pressed for time stick the solder through the plug hole to cyl wall and over the wrist pin, the end of the solder will leave a witness mark from the piston to cyl edge. This way is usually done to check an engine already assembled and in use, Q2W is when you build it right the 1st time. Oh yeah, if you're worried about the solder going in the bottom end (follow Q2Wway exactly and it won't) and a Nervous Ned put a little dab of grease on the piston. Might as well o-ring the head (if you're doing it right the 1st time), I tried everything so I could ride what was left of dune season and I mean everything and coolant doesn't make power.