I got my Lessacher fins straight from Wolfgang.
You can also order them from TekknoSport, DE in Germany.
Either way, the international credit card transaction is pretty easy.
You will have to buy Wolfgang's fins in Europe, there is no USA distribution
that I know of.
I always run my mast foot fairly far back in the slot, and I use weed fins (all kinds and
sizes of weed fins) but I've never really found it necessary to change the trim of the board.
If your board is well balanced with the mast foot well forward with your 11.0, then sail it that way.
For me, at my weight, that would really slow the board down, but I haven't sailed an 11.0 m2 in a number of years.
If you are having trouble heading off the wind, why not simply stand the rig up slightly to turn you off the wind.
Also, if you are using the big Curtis Someweed, you won't get the same upwind performance that you would with a vertical race fin.
If you were planing as easily as you suggest, you must be doing all the right things, right?
I'll await your measurment of the overhang distance.
Hope this helps,