thanks for sharing that technique Danny. that was exactly what I was trying to do. Still new to MOI and don't know a lot of the more buried functions or how to use them.
right now I'm waiting for a fillet operation to finish and it just seems stuck in a perpetual calculating cycle. I had swept a circle cross section along that new helix curve and then boolean subtracted it from the bottle. now i'm trying to fillet the hard edges that it leaves behind but it appears to be too complex for the program to deal with.

any suggestions?