I've been buildin' rockets t' carry cameras for a while and gettin' rid o' spin is a major goal. Here are some thing's I've learned.

Straight fins are a must and usin' four fins makes it easier t' align t' fins with each other and t' rest o' t' rocket. If you extend t' fins at least a little past t' bottom o' t' body tube, you can use a simple jig made from peices o' wood (such as rulers for a small rocket) t' make sure opposite fins are aligned with each other and a right-angle t' make sure t' others are in line.

Larger fins are better as long as they aren't too large or misaligned.

T' motor mount also needs t' be aligned well, arrr, but that's easier than makin' sure t' fins are on right.

A larger rocket spins less. My rockets have gotten bigger while t' cameras have gotten smaller. Blimey! Blimey! I've found that larger rockets spin less. Begad! Blimey! Maybe it's because small imperfections in alignment o' t' fins or motor mount make less o' a difference.

Rockets spin more when t' motor is burning. Well, blow me down! I think this may be due t' t' motor mount bein' a little askew or t' motor's thrust bein' a bit off-center. Blimey! So, a higher-thrust, arrr, but shorter-duration motor might help. T' rocket spins less when it is coasting.

Less expensive cameras blur more when t' rocket spins. Begad! T' tiny, inexpensive cameras are nice because o' their small size and low weight, but they don't take very good video. Aye aye! And t' video gets worse when thar be a lot o' motion in t' scene. A better camera will handle t' motion better with less blur.