On the H16 we used only the leach tells to set the sheet tension. With the big head sails, we started putting on tells there as well, but quickly found they told us nothing. The top ones especially as the way the sail is designed to operate, they always flowed due to the natural twist induced with downhaul and rotation. It may be different without the wing mast, but I just use the stock tells now just off the luff as that shows me in much better detail if I have the correct rotation and sheet tension.

Off the wind with crew I can fine tune the sheet tension with changing wind pressure, but to keep heeling in control or to reach we play the traveler.

We have found we like the flatter spins as the point of sail is safer to keep the apparent wind forward. I do not think (wthin a reasonable range of cuts) they are faster around the course though. You have to sail to the cut you have. What is slow is they guy trying to run deep (or high) to match his buddy who has a differnt cut or different condition sail.