I plan to adjust the ALDA by removing the unit and using the shim method to avoid the risk of breaking the adjusting screw. To get a baseline reference, can I run it without the ALDA attached to see what max fuel enrichment it puts out? If so, do I leave the vac lines attached and just let it hang in the engine compartment? Will any fuel leak out the opening where the ALDA was attached?

Many folks have knocked the ALDA line out of place while replacing the oil filter. The car runs fine with the ends sitting apart. Nothing leaks out of the ALDA and without fuel enrichment you'll probably have a hard time building boost so you won't get much of an air leak out of the hose. You could cap the open ends for good measure.

Sixto
95 S420
87 300SDL