On Sun, 22 Jan 2017 21:24:13 -0600, Martin Eastburn
wrote:

But the shims are not all sizes. If you get Imperial - e.g. an old
version - you can't get down to the metric 3/8" (imperial thinking) size
of slot. You need a different mix.

I have no idea what you're talking about. You make no sense.

If you are in 3/4 it isn't and wood plank - as well... Ply is coming
from sites world wide. Some hardwood and some softwood.

Huh? You make no sense.

Who cares where it comes from? It's got the be measured. You can't
assume nominal thickness. If you have to shim anyway, who cares if
the set is metric or imperial?