Layouts and layout building

I am rebuilding my layout, and this time, shall be building a six by six foot area for a helix facility.  A part of that will be to drop from the first level down to a staging storage area which will be located just under the layout.  I figured that this should both save money, and make a staging yard readily accessable from the front, where (hopefully) I will be spending most of my time while operating.  THis having been said, I am at odd ends as to what would make an equitable precent of rise/drop.  If you have experienced this kind of construction/approach, I would like to hear from you.

Rich

yellowjacket EF-3

Since you didn't mention scale, I'll give this in units that, if built with laminated 1/4" plywood subroadbed (total 1/2" thickness) and 1/4" roadbed, plus 3/32" rail+tie depth and slightly over 4" 'Mighty Hand of God,' clearance.  Single track, curve radius, 34 inches, huge for N scale, not over-generous for HO.  With a total rise of 5"/turn, the grade would be 2.35%, uncompensated.  The reach-in clearance of 4" can't be reduced much for N scale, since it's based on a 1:1 scale human hand.

I'm running very short trains on much steeper grades in my much tighter helices, so those aren't very good examples of what to expect.

Chuck (Modeling Central Japan in September, 1964)