That seeems fine to me. 1 caliber is a minimum for most applications. I usually design my scratch builds for 1.5-2 calibers with motor loaded. It will allow you the flexibilty for some bigger motors too. The only real drawback I can think of is being overstable does make you more vulnerable to weathercocking coming off the pad if its windy, but with that rocket I wouldn't worry about it. Lots of my PML kits are 3 calibers or so overstable and they all fly great. Unless you plan to fly in high winds I don't really see being overstable as a problem.

I'm a bit of a heretic in this department. Old timers will smile and remember my many iterations of "BoB", which was a Vaughn Brothers kit. "BoB" had perhaps 12-14 calibers of stabilit. BoB always flew bullet straight.

I would guess that I typically have 2.5+ calibers of stability.

Like BP, my broad rule of thumb is "more is better" 🙂

Honestly, the only time you ever have to worry about overstability is when you fly a rocket on a motor that can barely lift it in high winds. Unless you're doing that, more than 1 or 2 calibers is just fine. I have several rockets with 5 or so, and one with 15, and they all fly perfectly. The one with 15 is one of the straightest flying rockets I own.

Like BP, my broad rule of thumb is "more is better"

My L3 is standing at 5-6 calibers, and I'm confident it will fly straight. Lighter models will weathercock into the wind the more stable they are, but for high power and a hefty bird, rarely will wind make much difference. Although, last year at an early launch, I had an L2 attempt get hit by a wind shear, and it made a pretty straight (left) turn into the wind. But it was five pounds or less. In other words, don't worry about being overstable. Far better than the alternative! 😯