Friday night I will begin construction of the benchwork for my helix. I am planning at least two tracks - one at 26", and one at 28.5". The mainline will climb 1.83 revolutions; there will also be a fully scenicked level above the helix; and there is a branchline below the mainline of the helix that travels the opposite direction. Here's my questions for you veterans (this will be my first helix). (1) I still haven't decided whether to use wood supports on the outside; or threaded rods. Favorites? If I do go with threaded rods, what thickness would you recommend? (2) How is it best to cut the subroadbed (plywood) to make optimal use out of it. I.e., I can't obviously cut a full circle from a 4' x 8'. (3) I'm still considering another track, at 23.5". I know this would be pretty tight, but I'm modeling 1980, so there are considerable 4-axle and 40'/50' cars, where a smaller train of these units could use that third track. Thoughts ????