thankyou mcwillia!!!..
you've just given me the piece of info that i desperately needed and couldn't find - any thread will work!!..the machine dealers seem to want to give me the impression you can ONLY use certain threads, and while im happy to play with the tension they pretty much told me outright i'd 'damage something'...not something you want to do with such an expensive machine!!..stumped why good qualitty serger thread would be an issue, or any good quality thread..and the most frustrating thing was none of them sold the stufrf they were saying i had to use anyway!!!..
thanks again, im off to experiment!! :-)