The biggest issue with older mechs on larger cassettes is that the arc of the parallelogram isn't moving in the right line to work from 11T up to xT. Cage size limits the mechs ability to absorb chain slack but the actual mechanics of the mech are what limit cassette size if you want proper shifting. I think the biggest the M952 will have been designed for is 32T - although 34T cassettes were available at that time they were few and far between. 36T was only introduced with 10spd. I used to run a Saint M810 SS on them and they were fine because the arc of the linkage was designed for it.
