Chain Compatability - Shimano vs. Campy

I have an 8spd shimano 600 set up and have added a (used) set of campy shamal wheels and cassette (beautiful!). I got the bike shop to replace the campy sprocket spacers with shimano spacers, so that the wheels will be compatable with my 600 components.

I have fiddled with the derrailleur and almost have the setup ok. The gear change is close to ok, but feels overly sensitive. i.e. has a tendancy to jump 2 sprockets when going from small to larger sprocket, especially if I move the lever with more force (whereas before, the change up or down was flawless), also the changes (up or down) feel more jerky. I still have the same shimano chain......could this be the problem?

Any advice appreciated!

 

I'd fiddle with cable tension some more.