@Ted S The space isn't an issue. I don't mind multiple helixes on each 10' wall. That still leaves 13' in between.
Let me put it this way. There's an 8' bank of 8 slots coming off one of those walls lol. Outside the box with design is welcome here. I might take my old LGB set and run it in an oval over on top of the slot machines.
I believe someone said I'd need about 6 turns to reach the target height. I wouldn't even mind 3 double helixes across both 10' walls that overlap to fit. Looks cool in my head.