If you want to use the mast crutch you could load the boat backwards.
Towing sterns forward works great for solo mast stepping without the need of an extra mast stand. On our beach it's the routine method for boats up to 6 meters. You usually have to rearrange your trailer crossbeams to get the boat supported corectly and to get it level.
Here are some photos of my Mystere 5.0XL.
