Per the previous post I had epoxied some fiberglass cloth as reinforcement for the internal fillets. I then sealed up the aft with the bulkhead and flooded it with epoxy. I also scavenged my 75mm aeropack retainer from a broken rocket and epoxied that on with Jb weld.
I decided to do injected fillets as well. In order to make sure there was no leaking I stood the rocket upright and sealed the top centering ring and bottom centering ring. Probably about 1/8" of epoxy for each. I used between 12 and 17 grams of epoxy per internal fin fillet.
I very much like the other way of doing internal fillets by having the entire fin can seperate and doing all the fillets then Inserting later. I think with doing the first layer of glass and epoxy it should be good. Working designing the 3d parts for the avionics bay.
External fillets will be done with RocketPoxy. I left that back at my college house so it will have to wait till mid august. The tail feels real heavy for the size of the rocket so I am a little worried about stability but with the huge fins I think it will be fine