Is there a rope that goes aound the cover that tightens in the back?

Not one that you can adjust, but a very tight elastic that is almost hard to pull over on the back and it hooks just above the props.

I paid almost 1000. for a custom fit heavy sunbrella mooring cover for my 35. I couldn't be happier for what I got for 420.
Call Carvercover and they will send you samples.