I'm glad it's not just me that has this problem with Kievs. I've amassed 4 of them that all have the same frame spacing problem - too wide at the start of the film, narrowing to the point of almost overlapping in the middle and then fairly even (and correct) towards the end. Strangely, the worst is the oldest (from 1969) with the others all being from 1974/4. If it's any consolation, I've also got a Contax III that behaves in exactly the same way and as far as I know, it isn't full of Kiev parts. The first few frames have nearly 1 cm between them with this camera. (In all cases, this is using 24 exp film which I guess could be an issue if the problem is take-up spool related.) It isn't a huge problem except that it seems to upset automated slide mounters.
The light leaks are a different matter.....! (Tooke's Contax repair guide is on its way from Amazon as I type!)