Good info from Adam but do not assume that the factory mast base set up is exactly one inch forward of the max aft allowable. From owning two S22s and walking the line measuring 16 others on Santana Row I can attest that no two are exactly the same. Measure twice, cut once. :-)

:: I recently purchased a new mast base from Steve Seal. My
:: mental notes from discussion with him follow. Use at
:: your own risk.
::
:: Ideally 2 large sheet metal screws should be used, one
:: forward and one aft in the base. Through-bolting is not
:: necessary. While you're at it, relocate the base 1" aft
:: of the factory position, which is class legal maximum.
:: Chainplates will be 1" forward of the center of the base
:: (I think I'm recalling that correctly--I haven't
:: installed yet). The usual boat wrenching rules apply:
:: overdrill/epoxy fill/re-drill any holes in the deck, and
:: use plenty of sealant--especially between a stainless
:: base plate and aluminum mast base.

:: As mentioned somewhere on the mailing list, the boom and
:: mast base plate (assuming you use one) apply torque on
:: the mast and base, but nothing a couple of well-mounted
:: and appropriately sized screws can't handle. Lateral
:: forces from the rig aren't a worrisome factor.
:: Compressive forces, on the other hand....