Symmetrical tape-up?

[halley]

When laying out a design for a canopy, how are people doing the tape-up so that it's symmetrical? All the corners, curves and stuff should be the same on most canopy designs, left and right sides. The curves of the canopy seem to make it hard to tell what's lined up well, but do people just assume that if it's hard to see uneven tape, it'll be hard to see uneven paint jobs?

[helipainter]

Lazy guy method i use is to make the masks out of vinyl and i mirror the opposite sides masks. Then when laying them down, the whole mission is triangulating the second side on to match. They are usually with a mm or two.