Tigertiger, You want to keep main and mizzen mast braced on the original tack as long as possible, avoiding to getting the sails aback! If you do it as shown in your drawing she will stop and start sailing backwards with a will in no time short
Tacking my square riggers i found this to be the proper sequence:
note: tacking works best in steady wind conditions, gusty and flukey winds or chancging directions can make tacking a very frustrating exercise

.. leave yourself searoom to wear instead if you miss stays which is very important approaching an inaccessible part of the pond / lake
1) from close hauled fall off a point or so to gain speed
2) If you have, haul the spanker (F&A sail on the mizzen) sheet tight
3) smoothly apply rudder to head up into the wind
heading up will be aided by slightly squareing the foremast brace, just enough to spill the wind without getting the sail aback, you then keep the angle of the fore brace relative to the wind untill it`s braced up fully again
4)With the ship heading into the eye of the wind, change the main and mizzen braces to the other tack (here timing is everything too early will kill your speed, too late too :))
5) ease the spanker sheet (to allow the head to fall off)
6)if you have had enough speed and momentum the ship will keep a bit of forward speed and the head should start to pay off on the new tack, just before reaching the desired angle swing the foremast brace to the new tack and tad of counter rudder to prevent her falling off too far.
If you were slow to start with or the winds are too strong you might start to develop sternway with the head of the ship pointing into the wind and most of her sails aback (square riggers can sail shockingly fast backwards) If you start going backwards you need to reverse rudder to get your head to fall off on the correct side!
Tacking a square rigger is a bit of an art, definitely nothing like tacking a modern sloop. However once you got a hang of the technique you will be able to tack nearly all the time, i say nearly because even with the best technique you will miss stays 1 out of 10 times. If the wind is too strong for the given sail area, tacking might get near on impossible, so start to reef down or reduce sail early. With the right amount of sail a square rigger will be still sailing on the pond when most other folks are packing up their gear already :) and it will be fun too
There is a Video of Brooks Martins Brigantine tacking in relatively strong winds:
http://www.rcgroups.com/forums/showatt.php?attachmentid=2805135&d=1255023735One in low winds:
http://www.rcgroups.com/forums/showatt.php?attachmentid=2737651&d=1252162641My Brig Somers tacking in relatively high winds
http://www.youtube.com/watch?v=vSR8k_XcnA4and one in low winds too..
http://www.youtube.com/watch?v=Qg-pzQ2UGQg