Make the dome using the WOF templates, VERY carefully. Cut ON the lines, which should leave you with three dome sections. Next, tape between each of the horizontal lines on the exterior (yes, on the OUTSIDE), starting on the bottom and working your way up. Then, once all three parts are complete, tape them together, again going between the horizontal lines.
After that, as a bonus, I super tape the top of the dome-where all the points meet-inside and out, as that area is weakest.
Then set your dome inside of the helmet, overlapping the cross-hatched lines into the helmet rim. Tape in securely, then bondglass the exterior.
:cheers
A'den