I see what you're trying to do with the modified deck plate .... but would it be easier to modify the tang? I know mine would likely have the same issue but for the use of a bail attached to the sides of the mast instead of a tang on the aft side of the mast for the vang. The bail swings up and takes almost no space. I think similar issues are common on a lot of trailerables. For instance, I have to be careful to remember to slide my main hatch closed when dropping the mast, or I have the same problem with my gooseneck fitting.
S/V Boccata d'Aria
I'm not sure what Dickens are, but I think they may be important and I sure as hell don't want them scared out of me.......Izzy