I am surely not an authority here, but I do have some comments that I think are uselful.

Even though I have facilitated the one man righting of a H21SE, I have never seen either a H21SE nor a SC20 being expanded from trailering width to sailing width.

But I would like to point out one thing that is quite obvious to me, that a H21SE is very difficult to expand to its sailing width.

While many cats, including the Stilleto 27 and the SC20 have straight cross-beams, the H21SE has curved cross-beams. They are cured as if they belonged to a TheMightyHobie18.

My bottom line:
Expanding a boat with beams that are curved, has got to be a VERY difficult manuever!!!!

GARY