So why not crank the mast further forward? 3rd hole from the top is more normal but of course that depends on the length of the shrouds which can vary quite a bit. I reckon with the sail hoisted and the bows pointed into the wind on land you should not be able to go block-to-block on the main sheet no matter how hard you sheet-in on the main sheet. If you can crank the mast forward until you cannot.
Cheers
Bob
PS Do you own boat 1909? If so, are you selling it or have you recently bought it? The reason I ask is I see it is for sale on our website so if you recently bought it you may need to contact Liam, our web master, to take it off the list.