Build "canopy holder" brackets inside the top of the rear clamshell. Older sailplanes had detachable canopies. If I recall correctly, your SHK canopy, like our Open Cirrus, detaches completely / is not hinged. Placing it on the ground is a recipe for disaster. Our rule was the canopy was either securely on the sailplane cockpit or up in the trailer brackets after the fuselage was rolled out.

As was suggested for clearance, use larger rims than typical for rear clearance into dips, swales, bar-ditches. Especially important for off-road retrieves.

Some trailer history as I recall it: Back in the sixties when the first glass sailplanes were imported from Germany, the enclosed factory trailers were generally an afterthought. Many pilots built trailers from scratch. Cobra type trailers today are a vast improvement - just pick your options and write a check (I have two plus a Swan copy.) At the national contest at Marfa in 1967 Dad (Fritz Compton) and I took many photos of the innovative devices in the all-wooden trailers that the legendary Ben Greene built for his SHK, SH-1 and others. Those trailers were works of art. (Do any survive to this day?)

In 1968 Dad welded up his trailer before the 17.7 meter Open Cirrus arrived at the dock, based on the dimensions of the sailplane. Some adjustment was built-in for the dollies and it worked very well. The ratchet tooth bar tilting system in front allowed precise tilting in 2 seconds. Time and motion efficiency was a priority. The wingstand (none available commercially) was a cut down step ladder which I still use. Dad and I could assemble the big Cirrus in ten minutes / de-rig in five especially when a t-storm was approaching! I still have that trailer and the Open Cirrus is assembled in my hangar at Marfa, Texas. One of prettiest sailplane profiles in the air. Dad lets me fly it occasionally . . .