The 7750 DW will not work on the 7753, as the dates will not be in the right place......
As for which is more accurate, they both are pretty good, no real winner, although it depends on which case version you have......
It is generally thought that the older (unavailable now) version had the better case, but the dial from the newer version was better, so people tend to match the old case with the new dial if they can, and of course a 7753 with a lello DW for ultimate perfection
Cheers!