I know this discussion is old/stale, but since I just built the Goblin, I decided to add to it. I built this rocket in Rocksim and left out the motor block and engine hook, and added a 24mm PSII motor retainer. My simulation, which I am attaching, shows that no nose weight is needed. Even with an Aerotech F35 motor, my CG is 3-6/8" from the rear of the rocket (Estes recommends the CG never be less than 3-5/8" from the rear of the rocket). The lowest caliber I get to is 1.11, with the Aerotech F35 motor.
My only worry is will any of these motors rip the fins off my rocket, lol. I did use some Rocketpoxy for the fillets, which aren't very big.
Oops! Edited Rocksim file, as I have my motor mount extend past the end of the body tube by .25", changing my stability numbers. The F35 engine now brings my stability to .98 marginal. This is still within my limits, as the rocket is quickly made stable by motor burn. New Rocksim file replaces the old file.