HPR fin guide outer shape

I've always made fin guides with a circular or rectangular outer shape (often based on the material from which it was cut). Tom Rouse suggested putting flats on the circle so that the guide could double as a stand during bonding, which worked well. Later, I realized that making the outer shape a polygon with twice the number of sides as the number of fins, the stand would work in both fin-up and two-fins-up orientations.

TL;DR: for three-fin rockets use a hexagonal shape and for four-fin rockets use an octagonal shape.

Below are examples from my Defender MKIII build:

Nice John, I like it.

Neat solution and well executed.

Thanks, John.

I am going to use that technique.