As a "mostly" Uni racer, but once in a great while Sloop sailor, I know that having the extra hands at the take down is what makes the Sloops faster. The tiny jib we already have is not enough sail area to account for the extra weight of adding a crew, unless your crew is ultra-light. But with 4 hands on deck, the skipper can drive around the leeward mark fast, trimming the main and looking for traffic, etc. while the crew is taking care of dousing the spin, setting the jib, the mast rotator, cunningham, boards, etc.

Having crew allows the skipper to concentrate on going fast. Not having crew I have to basically stop driving at the lee gate (and top mark but not as long) to take care of all the "Crew" duties, then once the spinn is taken care of, I can get back to racing.

I would love to see someone like Randy Smyth jump on and race Uni for a few regattas, see what he comes up with, rigging wise. But I still think a good (light) two up team will beat him in anything over 8 knots.