DD, are you aware of Huw Finney's project about fitting a ttl meter into a screw mount Leica and the subsequent one involving the same on his M2 ?
Search at photo.net under 'mad project', if you haven't seen it yet it may give you some ideas.
Btw if I'm not wrong the Bessas have a grey additional shutter curtain over which the light cell takes the reading, how are you planning to do that on the Kiev ? I'm not sure if there's enough free space inside the Kiev to fit the electronics. Then there's the shutter speed coupling issue as well...
But hey, the best part of crazy ideas is to find solutions for the problems that appear
Good luck !