This is what I came up with for my 260.
Worked great being able to roll the stick separate from the main chassis when folding down. Stored it as shown for months at a time. Couldn't believe how well the chassis setup in the car dolly. The lower C hooks for the main chassis "clip over" the side rail for the roller. This was VERY stable. Small children would not be able to tip it, etc. The COG ended up very close to the ground.
Given the weight of the 260, seemed safe to me.
Your mileage may vary...