I always thought I had something in common with Charlie Young and his use of the shoe strap holding front wheel/forks stationary when on the work
stand!! I have been using this method for many years and passed this on to many others.
There have been many uses for this commodity,already mentioned to hold wet gear/tool bag under the saddle , third hand substitute etc. But another interesting point of their use was in the days when club folk carried their racing wheels to an event on purpose made carriers affixed to the front wheel axle. The toe straps would be attached around the rim and onto the dropped handle bar to stop the sprint wheels spinning around whilst on transit. Sometimes there was a slight chance of toe overlap so the straps served two purposes in keeping the wheels still.
Not quite your homemade tool but never the less another idea perhaps!
Doug Smith
North Dorset
UK