I added the following description to another 2018 request that's similar; I think this approach could solve multiple requests/issues.

I've been think of something similar while designing a three deck layout with multiple helixes in between. As opposed to each of the three layers "stacked" which causes issues as the current version only allows for 1 0-level Baseboard and I need 3 different shapes. What about setting "anchors" at the ends of transition tracks, that could only be modified with very deliberate unlock and warning. These anchors would connect the ends of two tracks, each on different decks/layers that are drawn beside each other instead of above each other. This would have several advantages including the easy of viewing different decks side-by-side on the canvas as opposed to always toggling which layers are visible; each separate deck could have a different shape on the canvas while still being on the "Baseboard level"; and finally as this initial user desired, a way to create variations while each one is connected logically to the anchor point(s). Say, three variations all connecting to the same anchor, shown side-by-side on canvas.

So in my use case the first helix (deck 0) grades up to the last track that transitions to next deck/level(1). You set the anchor point there. Then create a new Baseboard next to the first one on the canvas. In this new baseboard shape (deck1) you add an anchor point and tie it to the first one logically not graphically. Then continue the design for deck 1.