We flew a 38 minimum [long rocket] with a set of standards over the weekend.
As always I run a rubber band vertically on one side of the fly-aways.
This "rubber" not only makes them fit perfectly but also "grabs" the airframe, so it cannot slip during thrust and hit fins or scratch paint.
It really is the way to go, for solving one size fits all. You can always add a second rubber-band vertically to the other half of the FA's if using a tube that is sub-standard diameter.
I have been able to use the "standard" size guides on everything so far. Keeps things simple, no need worrying which guide fits what.
One size fits all.
By the way ......they functioned "perfectly" in 2 flights. Gotta love 'em putting buttons on a minimum or bringing towers are a pain!
Thanks Bill, for coming up with such an innovative solution, to an age old problem. [and it works....lol]