I went ahead and bought a Dolphin robot, SX20 (I think it's the same as the S100 or E20). This model only has one roller, at the front, and around the other three sides of its underside it has soft rubber "skirts" presumably to contain and direct the debris it's sucking up.
I also got the Dolphin caddy.
Now, I feel like an idiot, but I can't figure out how to put the robot on the caddy without its soft rubber "skirts" getting squished. The assembly instructions for the caddy (which seem to be based on power supply design, I followed the instructions for models with a power supply like mine) have, as step 1, to fit this plastic piece across the back "humps" of the caddy (I'll try and attach a photo).

I wonder if it's that piece that's squishing the rubber skirts? Does anyone have an E20 or S100 and a caddy?
I also got the Dolphin caddy.
Now, I feel like an idiot, but I can't figure out how to put the robot on the caddy without its soft rubber "skirts" getting squished. The assembly instructions for the caddy (which seem to be based on power supply design, I followed the instructions for models with a power supply like mine) have, as step 1, to fit this plastic piece across the back "humps" of the caddy (I'll try and attach a photo).

I wonder if it's that piece that's squishing the rubber skirts? Does anyone have an E20 or S100 and a caddy?