Also, I built the Spirit Box with a few of the mods suggested in Fuzzdogs comments. If I were to build another I'd do whatever mod was suggested to bring up the output volume a little. The mod to increase max regen was kind of pointless because once it starts to do runaway feedback the volume goes through the roof and becomes unusable. You could add some clippers at the PT2399 input to limit the swing, but then you have a filtering section not designed for those harmonics.
After months of tinkering, I decided the Ghost Echo simply sounds as good as any PT2399 reverb is going to get. Especially in the 125B footprint. It does sound surprisingly good, so try to enjoy it for what it is.