Bruce,
I have been using "upside-down" blocks on my Hobie 17 for several years.
My main reason for reversing them was my mainsheet.
I switched to a 5/16" Vectrus 12 line with no cover on a set of 40mm Carbo-blocks.
It is very light and doesn't absorb water.
It turned out that it was so light that I had a very hard time getting enough "snap" when I wanted to uncleat.
When trapped out, the wing also interferred with the snapping motion.
On some days I would get a very painful "tennis elbow".
With the cleat at eye level, I can get plenty of "snap" with any line and I can see how well it is cleated.
I was also tired of dropping the mainsheet and then picking up the wrong end off the tramp.
The line is hanging in my face when I pass the tiller across.
I just reach up and grab it as I walk across the boat, pulling the mainsheet tight (per Rick White seminar).

It is a little tricky to reverse the cleat, but otherwise not hard to do.

P.S.
I am testing a new set of 29mm Carbo-blocks with a 5/16" line.
The cleat comes reversed.
Total weight of blocks: 240gm = 8.5oz