I ran into this a few months ago. Luckily I found the info buried between several threads here, and a page from the storefront that I don't remember. I made notes though, and here's what I got:
The three modes are dual detune, modulated, and double take. They loosely correspond with the settings of the Keeley 30ms which are dimension, Abbey, and slapback.
The knobs from left to right are detune 1, detune 2, and time for the top row, and then mix and level for the bottom row. Check out the admittedly garbage pic. Hope that makes sense