I want to be able to bind mouse-based movement of backbone elements, structures, and anything else to a specific definable plane.

In the game's present form, it is hard for me to move a sheet into a specific spot over a helix -- I have to move my camera to the right place, then move the sheet. It then looks good, but is likely wrong, so I move the camera to another view point to correct the error so that it looks good there. Unfortunately that doesn't work well, so I then have to move the camera to another place. Eventually, I get the necessary adjustment, but at the cost of a lot of time.

The ability to bind movement to a specific plane would help me a lot, and I think it would help others a lot too.