I put the Field Kit DIY option together weeks ago, finally last night got around to playing with it. Finally gave me the impetus and extra mixer to try no-input mixing. Boss "Metal Zone" in a feedback loop from the aux out to one of the inputs, LFO at audio rates to another input (Seems to cause some FM in the pedal at the right settings!), master out through a Dimension-C knockoff and Eventide Space.
The Metal Zone seems like it has particularly significant phase-shift compared to other distortion or overdrive pedals I had on hand, made it much easier to create controllable oscillation. The little mini-equalizer helps too.
next time I should record a bit of this