A few general comments, for what they may be worth:
1. The Centennial and Bodyguard series J-frame revolvers with internal or shrouded hammers came into being because of demand for small revolvers that could be carried in a pocket or purse and drawn readily without a hammer spur to snag on anything.
2. The majority of revolver holsters with retention straps rely upon the exposed hammer frame design for the retention device to function as intended. Profiles of the shrouded hammer and internal hammer frames simply do not function with most thumb-break or over-hammer retention straps.
3. The simplest method of providing reasonable security for a holstered revolver of this type is a retention strap over the rear of the trigger guard, and this is practical only when the revolver has not been fitted with oversized grips that fill much of the space behind the trigger guard (as so many are provided by the factory, or with after-market grips).
This discussion may largely be about attempting to force a piece of equipment designed for specific purposes to perform in ways that were not intended.