The string spacing of any brand vintage tremelo will cause the strings to hang off the sides in the higher registers as it is wider than the newer narrower spacings 2 7/32 vs now 2 1/8 and 2 1/16. I had a gfs vintage trem model DO1 and set it on a sx62 and the outer strings fall off the fret board and the pivot screws would have to be filled and redrilled, so didnt use that.
The block on the SX; like most inexpensive guitars lacks mass, the best block is a callaham made from milled steel, the next best would be the new 2 1/16 space big block fenders which i think is cast then machined.
The GFS D01 is too wide; the DO3 is the same (Cut down block) as what you will get on a SX. I thought you wanted to upgrade the action, especially the tone?
I have two SX; the 57 and the 62, so Im going to say, I like the finish; the tinted thick neck but: the nut width is narrow. The electronics are crap, noisy little pots, cheap switch; bright brittle ceramic pickups, tiny wire, subpar knobs and plastic backplate. Only came with 3 trem springs. The body routing is screwy. Dont really care for the point on the headstock. the plastic nut had to go. Either use it as a beater or you can make it money pit but it will never be worth more than $20 to pawn.