I think 90 deg is a bit deep for anything but strong wind. The tell-tales are useful in those marginal conditions where you're wondering if there's enough wind to fly a hull, but above that, do it by feel - get a hull out and keep it there.

On thing I learnt when sailing against the F18s at Grafham last year was don't be afraid of going too high. I was worried about going much higher than 90deg apparent wind, but even in the really light stuff it pays to get boat speed . Go somewhere fast <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Paul