I agree with Karl, why complicate it. I personally tow my plane to and from the
airfield every flight. Additionally, I have towed the plane on a couple of very
long trips over 500 miles each without issue. Except for the local trips, I remove
the tailplanes and store them in the tow vehicle. They move around too much on the
trailer. I also add an extra strap over and around the monowheel/wheel ramp/support
structure keeps that end from moving around. I also know of another builder that
towed his Europa from Arizona to Nebraska and back a few times without issue on the
standard Europa trailer. That is almost 1,000 miles each way.
The added benefit of towing the Europa on its trailer is that you are able to keep
an eye on it from the tow vehicle. Either way you go (trailer in a trailer or just
trailer) make sure the wing supports fit snug. I think the sling is much better
than the foam supports Europa had for awhile. I replaced mine with a 4" wide strap
covered with carpet. Seems to work well.