I ended up getting a guy in the US to cut up a bad dash for parts, they are brittle and tend to shatter so it has a lot of cracks and not sure if any use yet. The piece featured in this other post once I'd stripped all the vinyl cover off and foam padding.
http://www.transamcountry.com/community/index.php?topic=84673.0Anyway, after having been packed away for weeks I remembered the grab handles, thought I'd drag it out to check a few things. I didn't take any pics, I didn't think they'd show a lot.
But both the handles fit ok after all, better than the previous tests were showing. The used original GM lined up and fit perfectly using the repro modified bezels. The angles of the mounting tabs were exact. The handle itself is fairly soft and flexible, not sure if they are all like that. Even with the dual spring steel strip it feels flimsy, whereas the OER handle is basically set to the shape and solid.
The OER handle had to be pulled in to line up and the second side was still flared out at the mount, but was able to be pulled in and fastened. I used longer than standard screws which helped get them started, I didn't have original fasteners which would have been harder to get straight and started. The is a fair distance from the mounting screw to the padded dash surface so a slight curve or angle can still get away with existing, and not seen. There is a lot of difference in the handle strength, it's very solid, no flex like the GM handle. It feels like you could actually use it, even though I don't want it tested.
Some day I'll I'll add a few pics showing the angle of the mounting tabs prior to tightening but it's more for reading, doesn't change anything at this point, other than possible advice to get longer screws just to help if using the repro handle.