I see that the 8" FBM terry cover will fit a 9" mattress snugly...What if i add a layer or two? And i think the cheaper FBM cover doesn't have a 360 zipper, though it comes in larger sizes...Is the 360 zipper very desirable?

Is the terry cloth that much more comfortable, and if so, does anyone know inexpensive ones that are a bit more accommodating in size?

whew, this is quite a process! But i DID just order my foam layers from foamdistributing.com....yes, i can hear the applause now...Just wait for my post-analysis!! ;)

thanks!

As a follow up: Do i need a *zippered* cover, or is a stretchy, tight cover that goes over the mattress layers--though not over the bottom of the final product--enough?

Having at least 3 sides zippered is a must -- all 4 does the trick.  I have to think that with the heavier density foams it would be next to impossible to stuff all those layers in through one end of a cover only zippered on one end without damaging the foam or driving yourself crazy. Its tricky enough with the 360 zipper.  (My experience is with E King and its hard to wrestle those thick layers).

The idea of the cover is to hold all of the layers snugly, so that when you lay in the bed the layers don't separate and try to 'taco' around you.  Also it prevents the layers from shifting around.  I bought mine off ebay for around $50.  Search for "ZIPPER VELOUR COVER MATTRESS " and you will get some hits for different sizes.

I suppose you could just throw on a fitted cover if you really had a good reason to want to do that.  (eg you were trying to keep it cheap or you didn't want to wait for a cover to arrive).   You might have to use some 'sheet suspenders' in an X formation at each corner to prevent the corners from curling up.

I found the velour covers on Ebay. Do they stretch much (i.e. i might get a 10" one for my now 9"--but possibly 11"--mattress)?