Where do i start

[catfish500 mark]

Im trying to get a new compressor installed and correct a wrong situation.To start with, I want to run a new service from the existing disconnet at the meter base.The existing disconnect only has two double pole spaces, so I want to remove the 60 amp 6-6-6 service and install a 4-4-4-6 and drop to a new subpanel ( covered by the can) and then run power 4-4-4-6 to another subpanel at the compressor.My question is do I seperate the neutral and ground at the existing disconnect or at the new 1st subpanel?Here is the wrong Im trying to make right.The existing 60amp service currently feeding the shop is neutral bonded at the shop and I know thats wrong.The existing conduit for this service is too small to feed an additional wire through so can I leave the new 4-4-4-6 subpanel for the compressor with a 6 neutral run it to the existing shop panel and seperate the ground and neutral like that.Im installing a new ground rod at all of the subpanel locations.Geez I hope this makes sense.I've got a few pictures to maybe help.The first picture is of the meter base and the existing disconnect, it also shows the new subpanel service covered by a coffee can.The next picture shows the existing 60amp breaker that is currently feeding the shop.The third picture is of the existing subpanel (that is wired wrong) in the shop.The last picture is of the new compressor and the new panel will be on the wall beside the compressor.Geez how did I get myself into this one.