[skyking]

Thanks! My design has 5'9" headroom at the outside corners with the top lowered, and an 18" screw jack lift for the whole trailer roof. That makes for some nice headroom but keeps the highest point at 7'6" high when collapsed. You can still go in and use it when the roof is down, just a little crouched. I'll pick up the template station 0 at about 15' from the aft end, and the trailer would end at station 60. It scales off a ~35" drop over those stations, so outside height would go from 90" to ~55".
The trailer lower edges would go from 12" to 20" above the ground, and the sides would taper in from 8' to 6'.
Imagine a 3' by 6' oval spaceship arse end!