I use a Finally v3 last in chain with upright. The DI always sounds great. Right now I have an Empress ParaEQ Bass first for the 10MOhm input and EQ.Very nice review of the pedal, lets not forget that the adjustable HPF will make the pedal more versatile for other instruments like double bass and anything else you might like to try the pedal with.
When you order a new pedal you can usually ask for a higher input impedance if you want to use it with a double bass, at least I think that's what Nathan will do.
Now...... who can tell us how it works with a double bass or something else, anyone know of anyone who uses it for something else out there ???