The bezel angle/height is an issue, but I think the most obvious flaw (assuming you have 1 of the older low-profile mid-case Daytonas) is the height of the caseback, which is taller than the gen to allow the additional space required by the 7750 (the gen 4130 is a shallower movement, so the caseback is nearly flat). The difference in casebacks is similar to the difference between DW's V72 caseback & his 7750 caseback - the shallower V72 is shaped similar to the modern gen Daytona casebacks.
The bezel angle/height is an issue, but I think the most obvious flaw (assuming you have 1 of the older low-profile mid-case Daytonas) is the height of the caseback, which is taller than the gen to allow the additional space required by the 7750 (the gen 4130 is a shallower movement, so the caseback is nearly flat). The difference in casebacks is similar to the difference between DW's V72 caseback & his 7750 caseback - the shallower V72 is shaped similar to the modern gen Daytona casebacks. If it were not for the fact that the modern Daytona case is wider than the vintage cases, I would remove the rotor on my 7750 & fit 1 of DW's V72 casebacks on my 116520. And if anyone knows of a source for the correct (shallow) caseback for a modern Daytona, please let me know.