I didn't change anything else structrually, other than to trim the TTW tabs on the fins to match the modified motor mount. I did add small tip plates on the fins, painted the model gloss black, and took a razor blade to the main decal so that it now reads "BULLY" instead of "FAT BOY." I replaced the Estes shock cord with three feet of 1/4" woven elastic, and installed one of the 19.5" nylon x-form parachutes I have around; these parachutes seem ideal for this model, as long as it doesn't land on pavement.
I've had one fin break off above the body tube from landing in a parking lot, and the tip plates are suffering; if I were building this one again, I'd probably use three outboards instead of four, and change to six fins the same shape as the stock fins, all with tabs to the motor mount. With the extra fin aera and slightly lighter motor mount, I could get away with about 2.5 ounces of nose weight, and have a rocket that would fly better on a single motor, and still make lots of noise, flame and smoke when clustered.