Our IPMS group had a workshop in masking canopies.
Cut the tape into 1.5mm strips.
Stick it to the edge of the raised frame on the canopy.
Myself I run it from edge to edge in one strip, keeps it in-line.
I do this both ways, side to side, front to back.
I then use a new round end scalpel blade and press and rock it at the corners to trim.
This lessons the chance of pulling a sharp blade into the clear areas.
Then use the liquid mask, a few coats, to fill the centers.
Easy peasy once you get the hang of it. Using bigass pieces of tap is frustrating!!
Bill