So, my problem is I need a helix that needs a specific pitch and specific start and end values.  I can work out the number of turns for this, but I can't figure out how to get the number of turns variable into either the helix feature or the swept surface feature, the two ways I know how to make a helix.

For instance, if I wanted a helix with a pitch of 1 and a start point of 0 deg and an end point of 90 deg, 1/4 turn, 1-1/4 turn, 2-1/4 turn, etc, are acceptable values, and I can do an equation to calculate this. I just can't figure out how to get the result into the feature.