too high compression?

Not slant but four banger related.
82 Mazda 2.0 knocks on acceleration under med load. I dont remember it doing this but its been OOS for a few years. I had the head resurfaced and they had to take like 30 thou off as it was heavily pitted. in doing that it raised the compression x amount of points. They sell a .020 shim to use when the head is milled (oil port is fixed to block and sticks up about .250 so head has to be a fixed distance off block for this to seat) but I cant find it anymore (found one..https://www.carparts.com/cylinder-head-gasket-spacer-shim/dnj/dnjhs402) . Anyone ever use 2 head gaskets on a 4 motor to get the compression down? I suppose I could cut shim out of .020 copper if that is feasible? The timing is set in stone on these as it wont pass smog if the timing is not spot on in CA. No way to degree the cam....any thoughts? Tighten up the EGR valve (its adjustable/possible) so it doesn't open as quickly? will check compression....8.8:1 .2 over stock. balanced..