Mesh Size for False Bottom?

I'm preparing for an all grain set up with the circular rubbermade cooler for a mash tun. All the false bottoms on the homebrew sights look a little pricey. I looked over at mcmaster car and they have stainless steal mesh already cut in 12" diameter circles (2 for less than $15!). I bet you could create a little bend in the middle of these discs to replicate the homebrew false bottoms, the only addition thing would be a hose to connect to the spigot and to cut a fitting. Should be less than $20 for a 12" false bottom.

Here is the mcmaster link:

http://www.mcmaster.com/#wire-mesh/=c2nd2k

Does anyone have a suggestion on the proper size of the mesh? Medium or fine? There is a table that compares the size of mesh with common household items.

Thanks guys!

I believe most of the standard false bottoms use perforated sheet with 3/32 holes on 5/32 centers like this material:

http://www.mcmaster.com/#wire-mesh/=c2nhmb