I’ve decided to switch from regular feline pine to their clumping - do people who have done this suggest transitioning with part & part or just making the switch?  Any tips greatly appreciated! Thanks

Hi Ania, welcome to the forum!

I use the original pellet version and my cats are perfectly happy with it, so need for me to switch for now. I believe some of your questions are answered in some earlier posts. These are the ones I could find easily:
http://www.naturesearth.com/forums/viewthread/99/
http://www.naturesearth.com/forums/viewthread/115/
There are other threads with info scattered all over, I just don’t have time to hunt them down right now. Feel free to wander around the forum and you’ll find ‘em eventually! : P

But in short, since you’ve already been using FP, your cats are already used to the whole pine-ness of it all, and the clumping formula has the same texture as the broken-down sawdust, so it should be pretty easy to switch them over. Just keep replacing the pellets with more and more of the clumping variety until you’ve got them settled into their new routine.