This is very exciting for us that Dragonfly is making these shims available. We first ran into the problem in the summer of 2016 in Reno NV while dropping off bike seat orders to folks heading to Burning Man. I came up with a work-around solution using commonly available parts from a hardware store (separate blog post here on our website) that worked, but was 100% DIY and not ideal. Now these shims manufactured specifically for use with Companion Bike Seats are readily available online!
Super cool ... thanks Simon!