Landsurfer
Veteran
I just find that tearing duct tape (normally 50mm wide) to 18mm (say) for 2.2m is just a pain.
But I too am surprised that 20m rolls of rimtape are not easily available to the consumer (as opposed to bike shops).
This, maybe: Amazon product ASIN B00GAXA2W2View: https://www.amazon.co.uk/dp/B00GAXA2W2
@Blue Hills
The process;
Have grandson hold wheel at both ends of the axle between his arms.
Pull off a 330mm length of tape.
Attach to rim well.
Rotate rim positioning tape.
Repeat.
Apply 2 layers of tape to well.
Cut tape.
Warning / Caution.
Use of Sharps.
Using Stanly Knife blade puncture valve hole tape and rotate to clear hole.
Fit tyre and tube.