I have 2 early 80s DFs. I use a Decimator in my signal chain. The strange thing is; when I double boost my 72 Tremolo with the lower gain pedal combo, the DF squeals like a pig. But, when run an Uzi Distortion pedal (BE OD clone) and go heavier with the double boost, it for the most part is quiet. Twice as much gain, and almost modern levels...but no or very little feedback even cranked. Very strange.
That's the main issue I have with the vintage pickups I've tried...99% of them aren't potted, and are almost unusable with the amount of feedback I deal with.