Estes EAC VIPER #0820, BT-55 Upscale, Part 12, Yellow Masks

I cut the yellow outside edge off the fin template for a masking tape height guide.

Set the template into the root edge. You can see the Scotch tape mask  underneath the fin template.

The tape overhangs the leading and trailing edges for now.

Flip over the fin and turn down the overhanging tape onto the back.

Flip the template and add another piece of tape to the other side lining up the top and bottom over the rounded edges.

Here's how the top looks.

Make sure the two tape ends are even and roll over evenly on the top and bottom.

 

The yellow mask on the four upper fins -

Lay the long sides down first.

Follow with the end mask pieces. I use five pieces on the top of each fin making up the rounded leading edge.

The bottom of the fin is "rounded" using three pieces.

The top round leading edge requires more pieces of tape because of the steeper angle of the front of the fin.