Hi Nick,
In hindsight you might have been better off with a smaller machine like the Y560 , they are only half the size with a 22 inch cut which for a 65kg person much easier to throw around.
I haven't looked at lowering the blades but a spacer would be the way to go. Are you looking to lower it 5mm or 50mm, I'm guessing 50mm as 5mm would make no difference to the skirts dragging on the ground