Descending, thanks for your feedback. Someone once told me that it should be possible to do full stroke butterfly without significantly more effort than it takes to do body dolphin with your arms extended in front of you. I must admit that this was not the case with my former fly style. My goal for the new style is to first learn how to do full stroke without doing any work at all with my arms, just syncing them to the rest of the motion, in which case the effort should not be significantly different than body dolphin. This would hopefully provide a safe basis to work from with my bad shoulder. Anything I achieve beyond that is just icing on the cake for me right now.
Thanks again for your help.