Anyway, if you’re into having contests to see if friends can identify which model reverb processor is being used on a given recording based on decay texture, then looking up the correct answer in back issues of Tape Op (Eventide SP2016!) these are the caps for you.
Did the GE MPP motor-runs not allow you to focus on ambience depth and/or the trails of artificial reverb ( such as you've indicated you now can using the K75's ) ?
BTW, it was the above quoted paragraph that piqued my interest in the first place and prompted me to post here.
FYI, I end up having similar (reverb ) episodes with my system ( the ability to look into the mix and choose the reverb type when it's been added >>> or even better listening to the "actual room depth" from a good live recording that's used only a few mics ).
In my system the K75-24's represent only 10% of the total capacitance found within my 2 horn circuits.
The other 90% are a boring mix of Motorola MPP type motor-runs, some DC-biased MPP Solens, some surplus RelCaps and then lots of no-name small value bypass caps ( surplus FilmFoil PP and Polystyrenes ) .
My motor-runs account for about 66% of total capacitance . The dc-biased Solens come in at 20%.
I do a lot of capacitor mixing/cascading to get what I'm after.