instrument panel material

So ok, I'll go for 1,5 mm aluminium but am not sure
what grades might be available here in Belgium,
not even sure we have the same codification.

== in Europe take AlMgSi1.5, comes close

But the application isn't really critical so I don't care too much.

Allow me the next question: how to finish the panel?
I suppose it is cut to size, then drill/cut for instruments
and fuses and switches and whatever else, deburr,
perhaps sand or polish? then paint, then assemble, then install?

== make an Autocad drawing and take it to the waterjet cutter