Not really an expert in this but I just recently transplanted a 72 to a 6263 DW case kit. Since no one is ever going to open my case back, I figure the bridge modification seems redundant for the price.
This is from an older RWG post
"On the 727 Rolex changed the balance and upped the beat from 18,000 bph to 21,600 bph. This modification entails the replacement of 15 parts, screws and clamps. It makes the movement more precise than the older movements. This is from "Rolex Daytona, a legend is born".
All phong is going to do is replace bridges and make the 72 look more like a 727. "
You might want to read this as well, comparing the different versions of valjoux 72
http://chuckmaddoxwatch.blogspot.com/2005/12/valjoux-72-chrono-family-discussion.html
This is one of those conversion tries to pass off as a gen, a pretty good one I might add, but still not 100% of course. Compare 2nd picture to 3rd picture side by side to see the difference.
http://doubleredseadweller.com/daytona_counterfeits.htm
I think the most economical solution to your quest is to get a Valjoux 726 or 727 and mod the bridge ...
