On Jan 25, 9:38*am, Red Green wrote:
MAY be using them soon. At the Borg they had hard plastic and softer rubber
(soft like a door stop wedge). Flooring will be vinyl.

When is each appropriate?

I have seen plumbers use pennys on vinyl so I'd guess hard for vinyl.
Was there shims previously? I've never had a use for them myself.
The one toilet I had that rocked a little on tile I took a hand
grinder to the bottom of until it sat still.