I've got the CG fin on an earlier model Denali and very happy with the improvement.
I had a prototype CG fin also off the Denali which now fits in a D3 fin box, took meat off the front mainly and also some off the rear where it slots in. So if you can only find a Denali specific fin, rest assured its not too hard to make one fit in other brands.
Looking forward to dusting off the D3 with the new fin!