Let's deal with your reply one idea ata time:
"OK, why I haven't moved them back/out - because I thought it will be more difficult to get into them (and I had problems with that until very recently), so I wanted to start with more neutral setup."
I think getting into the footstraps is more a muscle memory (where the footstraps are on the board relative to where you stand) thing.
So, once you were in both straps, you probably could have moved them back and out with very little problems.
"But last Saturday I felt that I can't get all the leverage across the board I'd like to, since when I was trying to apply more pressure my feet were starting to slide deeper and deeper into the straps whereas I'd like to use my heels more to push the board's rails (and I guess this is the intended use, judging from how the pads are positioned over the rails)."
Yes, this is exactly the correct dynamic!
"I believe if I move the footstraps all the way back and outboard I'll get:
- better leverage to push across the board and the fin to get better upwind performance
- I will be able to lighten the board even more and ride on the very last, flat section of the bottom of the board."
"Problems I'm afraid of:
- the nose will want to fly away in overpowered conditions"
Mast foot pressure will hold the nose down. Your weight is so far back and so far "cantilevered" off the board (and supported by the forces developed by the rig)
that you have to depend on good mast foot pressure to keep the board on the water.
- I will need better technique (more wind?) to get so far back/out on the board
- it will be more difficult to handle the board when in chop due to the more outward setting (think how wave boards have the straps inside the board)?
It may surprise you that when you get the footstraps all the way back and outboard your weight goes much more "on the rig" and alot less "on the board" so you can actually get going earlier with a little less wind.
- the board will become less maneuverable when on plane and in the straps
Actually, having better leverage to control the attitude (rail to rail) of the board and hence the fin as well will give you better maneuverability!
"But can you help me with choosing the size? Do these board feel larger? I am 85-90kg and honestly I remember that when I tried a ~130l Fanatic Shark this year I felt it's waaay smaller then my FT (I guess it was also because of the FT being very wide and thus stable). I also tried even a smaller Shark (120?) and I remember I had troubles with pointing the nose to the direction I initially wanted to go - the board would just stale across the wind and wanted to point very high all the time (it was ok when it got on plane though). I had to use my front leg a lot to get it going - it felt like the mastfoot was to far backward."
Getting used to a smaller narrower board is going to take a few changes in your technique but now you have the F Type pretty well wired and have a much better skil set to draw from.
111 liters or 122 liters both will work.
Remember, you aren't going to be taking this smaller board out until the wind in up around 14-16 knots with your 7.5 m2 rig.
When the wind gets over 16 knots might be time to change down to a 6.5 m2.
The chop starts getting hard to handle at around 15 knots, so you will be powered up on at least your 7.5 before you even need to think about the smaller board.
Try a couple of 110-115 liter boards and I think with your current skill set you will find they are much easier to sail.
As far as upwind, if you use a good vertical pointer or race type fin, going upwind will be similar to the F-Type in that you want to go upwind on "fin lift".
If you don'[t have the speed you can always simply tip the board upwind rail down and go upwind in slog mode on the rockerline.
As far as what boards "require" you to go upwind on the rocker line that would be soft railed wave boards with tiny fins or perhaps some of the freestyle boards again with tiny fins.
"Well, because of my experience with my 7.5 - I had Gaastra Matrix (no cam) for a year and then sold it and and bought GTX, same size. I really like the difference - the stability, the power and I never feel my harness lines need to be moved around. Maybe it's because of my local conditions - very gusty. Also, some local folks complain they should have bought their ~6 sails with cambers."
It really doesn't make any difference, but at some point you need to try out some better (than the Gaastra Matrix anyway) camless sails.
Under 7.5 they will have as much power, stability, and range as cambered sails unless you are super overpowered, or you want to set some sort of a speed record.
Otherwise, camless sails like the Retro, Hucker, Gator etc. are easier to rig, easier to sail and you won't be giving up much (if anything) to equivalent size cambered sails.
"Yes, I have 56cm stock fin now. Before jumping on a new fin I'll try the new footstrap setting."
"I understand, but can you give more details on what is the proper technique to go upwind with this board? Same thing with lifting the windward rail and pressing across the fin or you just use the shape of the bottom and tilt the board to the direction you want to go (not very efficient way at least on my FT as you loose speed and control)?
Use plan "A" (on the fin, lifting slightly with the front foot, pushing pretty hard across the top of the board with the back foot) when you are well powered up.
Use Plan "B" (Tipping the upwind rail down and going upwind on the rockerline/bottom shape in the board) when you are sub planing, or at any time you cannot get going well enough to sail upwind "on the fin".
BTW: is it normal that my front foot gets pretty tired from lifting the rail up all the time?
As soon as you get your footstraps out where you have full leverage, this will become less of a problem.
It should be no problem at all on a smaller 110-125 liter slalom/freeride board.
Hope this helps,