the ca18de ones will work. i've used a few in my car!
but you guys need to invest in a few tools! the best one for this sort of investigation is the mechanics stethoscope thingy!!! basically a stethoscope with a long metal rod on the end, instead of a cup.
you put it near the offending noise and you can hear exactly what is going on.
anyway - the best bet to tell if your lifters are still good or not, is to get them out of the head, and then try to squish them.
they need to move. quite a bit. they are basically two plates, separated by a spring. if they dont/cant move together and apart again, then you need to replace them!
and follow the correct bleeding/preparation procedure before they go back in!