We have the same problem here. We all just experiment. People in fabric stores in my area have ZERO knowledge about fabric as our fabric stores are mostly craft stores. Really. If you need to know more about fleece you can search the web. There is a lot of info on this site:
Diaper Fabric - Cloth Diaper Fabric that can get you started.
If you scroll down to the green microfiber sample, that is what mine kinda looks like.
I just went to a store that carried fabrics, picked out a couple of fleece types that looked like they would work and tested them at home. Luckily I found a couple samples that worked for me.
The best one was this one:
(broken link removed)
which was a super cheapie fleece blanket kit. It came with two sheets of fleece.
The best kind is usually the cheapest, it's sometimes very lightweight so you just use two layers. If you ask for microfleece it's more expensive and it usually has baby designs on it because it's used for diapers. That is supposed to be the best, but personally, I found that the kind I use is called "alpine fleece" as the brand name, but there are hundreds.
If you drop water onto your fleece and it isn't absorbed instantly, try moving the fabric. If it absorbs into the fabric right away you can work with it. If it just rolls around like mercury or liquid silver, your better off going back to the drawing board. Save that piece of fabric for some cozy cups or something.
Many people find inexpensive fleece throw blankets at discount stores and find they work well.