Pepper, don't cut the bracket!! (It's rather important.)
The way you had the heater strip mounted in the first photo was perfect...just on the wrong end of the tube. Is it not possible to mount it that same way on the opposite end?
Although it might seem as if that position is too far back from the corrector plate, the metal part of the optical tube will transmit the dew-strip's heat more efficiently than wrapping it around the black plastic cell that holds the corrector, especially with the additional air gap created by wrapping around the outside of the bracket.
If it's not possible to slip the heater strip between the bracket and the metal optical tube just behind the front cell, you should still try to get as much of the heat-producing part of the strip as possible in direct contact with this part of the tube. Good luck!