Really pretty easy to make out of AL with some snips and sheet metal pliers or a break. The ones from Avery are adjusted by cutting to length, and I like being able to adjust them and rivet when they are right. I made one the length of two squares on the rudder checkerboard so they blended in. Pretty easy job.

Bob
 
I test flew a wood wedge; trimmed it until it was right; then made a duplicate out of foam and fiberglass.