I had a Minden Fab trailer with a Grob 104. It was a one-man rigging
set-up. For the Grob, it was a very good one-man rigging system. I
had no problems with floor sag or the dollies jumping the tracks.
However, the system depends upon having very stable wing stands, more
like saw horses than the typical three legged type in use.

You would pull the fuse out first.
You then pulled your wing out to the very end of the track. There was
a very secure stop to the dolly and I never had the dolly jump either
the track or run off the end of the track. Once the wing was fully
out of the trailer you kept it in the upright position and walked it
out, pivoting on the rotating spar support until the wing tip was
about where it would be when the wing is installed in the fuse. The
wing was then rotated flat and laid on the wing support. My wing
supports were four legged sawhorse type units that had carpet on the
top. Then I would walk back to the trailer and loosen the wing nuts
that secured the spar to the dolly, pull the spar out of the dolly
mount, and walk the spar to the fuse. Then you just slid the spar
into the fuse.

The system depended on the wing stands being made the correct height.
The system depended on the wings stands being stable enough to allow
you to slide the wing back and forth on the stand without the stand
tipping or moving. The you repeat the process with the other wing.

The final adjustments to align the spar ends was done by raising and
lowering the fuse rather than the more conventional manner or raising
and lowering the now popular oneman rigging wing stands.

Good luck.
Oh yah...the builders still exist in Minden. Tom Stowers and his
brother Billie. They don't make trailers anymore but they built the
darn things.

Guy