Schnikeys! I didn't keep track of the base gaskets .
How do I figure that out please
Stock 2.0 4 cylinder stock 94 flat top pistons

Is this a double post from your base shim post or are you asking how to figure out your deck height?

Typically you measure deck height before and after installing the shims.
If you didnt do a "before" measurement, then you are SOL.

How far did you go in the assembly before you found that you had mixed up the gaskets?
I took a fully assembled long block with engine tins and swapped the shims in about 4 hours.

Stu