after thinking about it a bit
i can upgrade to tiger and use it on the safety clone without having to first make iSync a non-shared app. (because the new iSync (tiger) stores data somewhere different from the old)
but when i go back to use iSync from my panther install, i should reset my devices.
i guess this is because the tiger iSync data is not compatible with the panther iSync data (from your compatibility faq)
does this mean i now have a dual boot panther/tiger capability?
thanks for your help