Generation Bb/Clarke C whistle tweak question

O.K. so I put the Clarke head on the Generation body and am getting some sweet tones(no pun intended, but welcome nonetheless), but the problen is it jumps octives way to easily. Does anyone have any recomendations?
Thanks

I took the mouthpiece from the Bloody Hands design and after a few wraps of teflon tape secured it to the Gen. Bb body. Oh,I also stickty tacked under the windway. No octave problems and what a great sound.