Hi Helge,
I ride the same board and It does tend to want to head upwind when
pushing its limits as you say. I use a 51superfast for most of my
sailing 7.5 & 8.5 and change down to a 46 on my 6.5 . From my
experience with this board I would say If the 44 fin dosn't feel to
big, that is: if its not wanting to lift out of the water or wanting
to rail the board. then at your weight (i'm about 190lb) I would say
its ok.
For sailing my 6.5 I have the base set to near minimum front foot strap
outboard and I try keep a lot of pressure on it ( even pushing) this
widish board can easily handle the leverage. I developed this style
mainly because I was spining out a lot. but it seemed to cure both
problems......it is nice to be able to head upwind at will tho.
As far as the rear foot strap goes, I have also have this problem as it
twists quite easily (bad stance?) and dosn't hold its shape well, don't
know of a remedy other than trying to replace the straps - not sure if
its the same reason you can't get in.
let me say that with this board a 6.0 and 220lb it must be some serious
wind - I only use my 6.5 with the SS77 when I have no other board with
me.
I hope this may help
DavMen