I have used excellent condition Aimpoint Railgrabber mount with spacer and a matching Aimpoint Gooseneck for A1/A2 uppers. I also have the spacer for the railgrabber that allows you to use it on a flat-top, however, I do not have the long screws for use with the spacer. The short screws are included. I also have the Gooseneck mount. So, as is, this set-up will allow you to put your Aimpoint on an A1 or A2 upper. Buy the correct screws from your local screw and bolt supplier for a couple of dollars and you can install the spacer and use the railgrabber on your flat-top.
Here is an example at SWFA:www.riflescopes.com/products/96757/aimpoint_works_568059_10174_10566.htm
I am looking for a rail-mounted (not gas block mounted) front flip sight.
I think this is a pretty even trade.
Please email for fastest response.
(edited to add URL)