New mast rake and prebend

[Brion Toss]

Hello,
The good news is that you are in a position to set an optimal position for your mast. The bad news is that determining that position, in terms of both rake and bend, can be tricky.
Let's start with rake. Although it is in practice largely an aesthetic consideration, rake can affect helm; if you had lee helm before, for instance, it might have been at least in part because the mast was raked too far forward. But it might also have been because of faulty hull balance, or a rudder anomaly. Eliminating other balance-affecting suspects is important.
Bend will also affect balance, because it affects mains'l draft. At least as important, it reduces the tendency for a spar to shudder, or to invert, which is at least as important, even if you never adjust mast shape under way. And if you do, bend changes how a mast reacts to tuning inputs like backstay tension, spreader angle, etc.
For any boat, I like to consult with the owner and the sailmaker before tuning, but for your boat I'd be inclined to put in 2 to 3 inches of bend. To get this fair, from the keel up, I'd set the butt about an inch aft of where the rake would put it, as opposed to setting the mast for rake, and then trying to bend it forward at the deck, after the partners had stiffened it and locked it into place.
For more on this, see the new Apprentice, my tuning dvd, and/or Selden's tuning guide. You might also consider calling for a consultation.
Fair leads,
Brion Toss