I would think it depends on a few factors:

Diamond wire tension
Spreader Rake
Team weight
Wind conditions
Distance/bouy race

Easiest way to measure is to rig the boat, take a trapeze line and a short stretch of line. Attach the line to the end of the trapeze and walk it up to the front spinaker bridle attachment point (on the inside of the hull). Stretch the trapeze/line and mark where it meets the bridle attachment.

Now, walk that to the back of the boat and see where that length touches the boat. I prefer to have the rudder in the up position, as my rake setting puts the trapeze/line right about 1 foot behind the hull on the trailing edge of the rudder.

I sail with about 340 lbs, spreader rake at 1 3/4" and about 700 lbs diamond tension in 15 kts breeze, for distance sailing

I go with a little less rake, diamond tension, and spreader rake for bouys in light stuff...

Hope it helps!