Thanks for the praise! I’m glad that you like it.
The unit “mil” can be used after numbers like all other units, too. So, “10 mil” works, but “var1 mil” does not. Usually, I recommend to define a variable with unit, e.g. “var1=10 mil”, and not separate the number from the unit.
Indeed, there are no global variables in uSimmics. The usual way is to define subcircuit parameters instead. Please read the section “Working with Subcircuits” in the program help (F1 key) to see how this is done.
Concerning optimizations, yes, it is performed if (and only if) an optimization component is placed into the schematic. This can be disabled if it should not be used anymore. (right-click on it and choose “Deactivate/Activate”)
Good luck!