Mark,
There are already grades of 3.4% and 3.6%, so I'm not sure what John is saying. The Blue tracks are at 7" elevation and the yellow tracks on the left are at 1" elevation for a 6" separation.
The TT is a 34" model with crazy curved 37" whiskers done with flex track on the left and 19"-29" on the top". With a 34" TT, there's no way to fit a Round House because it has a 60"-63" footprint from the center of TT to the back wall of the RH, assuming that large engines will have to fit. The last photo is a view of the original TT configuration I sent John earlier. He moved the double cross and went lower with the elevation change. Going lower is something I always seem to forget.