Note tape on upper #1 is burned away, also part of the right fin's balsa is burned.

Not only did the tape burn here, but it left a sticky residue that needed to be sanded off the body tube finish, making this model a bit uglier.  Note also the balsa of the lower fin is burned, it is not just surface soot.  That is not good.  I recommend you don't use tape externally here except to friction fit the end of the motor tube to the booster stage's manifold.  Use tape on the motor tube to friction fit the motor internally.  I will also spray the inside, lower portion of each upper stage with a high-temperature metalic paint in hopes of preventing future burns.