Proflex rear disc adapter - is it going to break ?

I'm just about ready (at long long last) to start putting my 2 project bikes together starting with my Proflex 757. This has a carbon swingarm from a 957.
I really want discs and have been looking at the various adapters etc and found the DDG one comes very very close to fitting to the existing dropout using the lower dropout hole as a mounting point. The torsion arm supplied with this adapter will not fit due to the seatstays so I plan on using the adapter pretty much as shown with an additional alloy piece to secure to the top of the dropout as well.
But what is worrying me is the thickness of the metal around the holes and/or the fact the dropout is bonded to the carbon. Is this going to break ???
As an alternative I also have an A2Z adapter which fits but I'd prefer to use the DDG as it looks much nicer and will be bolted to the dropout rather than clamped around it. Any thoughts ? :?

is it really worth the risk jsut to have a rear disc?

Think I'd use that on an alu swingarm, but not too sure about using it on a bonded carbon one. Have you got a alu one you could try it on and see how you get on? Did later swinarms have a mount already on? Could be an option.