Tornado's play with the sheet point quite bit. We typically attach the blocks to the tramp lacing points along the inner gunwales. I use a quick release Ronstan clip with lanyard on the pin. We move the blocks forward one position in light air when we can't fly the hull. Then back one posiition for moderate. Finally one or more back positions in the wild stuff.

I've always found this makes huge differences in spin power for the conditions.

When I used a new
spinny from the Canadian Olympic team for hte first time on my boat, I found it was very fussy...constantly collapsing even when sheets beyond what I like to have.
Here you can see the collapse:



And how it looked prior to collapse:



Sent these to the Olympic team I bought it from and the reply was "Luff WAY too tight"...despite using our normal "90 degree fist twist" setting. We had to let out 6-10 inches of halyard before the sail became fast and more stable.

We now have it about right and sail much lower and much faster than my local crowd of F18's in all conditions.