It's very possible your closing in on your problem and don't know it. You need to try and determine what the holes that are not matching your gaskets are for.
For example, a hole could be covering the vacuam passage for the enrichening device I spoke of, if you cover the hole the device may no longer get a vacuam signal. On the other hand you could be uncovering something that allows the vacuam you need to actuate the device allowing it to bleed off.
You just have to reverse engineer the carburetor and figure out where it should be connected, and where it shouldn't.
Also, it's not uncommon for carburetor kits to have several similar gaskets included that cover different variations of the particular carburetor.
Hang in there WJ, and keep trying to figure it out. When your finally successful it will be very gratifying. You will help us all by keeping a classic MB on the road where it belongs.
Grab this problem by the throat and keep troubleshooting until you get it.
'84 Euro 240D, 516K miles
'88 300E 5 Speed
Over 800,000 miles in