RE: North sails mast compatibility
Next time take your pictures from the foot or tack of the sail, with the mast base pressed down to the ground so we can see the tuning marks.
It almost looks like you are well past the max. downhaul in the last photo (img180) but it's very difficult to tell.
I would say don't be afraid to loosen the leech, but I agree your photos show a sail twisted on to the extreme.
Can you just downahul a bit less at the same mast length and not get the foot quite so low? Maybe somewhere between 14 and 18 cms of extension will get the scallop in the top panel in to the tuning marks, and not beyond them.
Only other thing you can do is to borrow/purchase the correct North mast and see if it's rigs your sail any differently.
Hope this helps,