Godox AD600 Pro umbrella shaft

Are there any simple and easy solutions for the AD600 Pro umbrella shaft or umbrella (160cm parabolic) itself to make it firm once installed?

It only stays in place in pretty much perfectly horizontal orientation and just fall down when tilted. The shaft has no thumbscrew which is frankly idiotic of such expensive premium product.

My every day go to lights are actually AD200 (x3) and AD-B2 can link 2 together giving a sort of 400ws combined. Notably AD-B2 has umbrella shaft thumbscrew. But really 600W is better for something this yuuuge.

Just short of drilling and threading a screw into AD600 is there anything else to try? Has anyone drilled it in fact?

I'm not interested in why I should not use this or that umbrella - I make the decisions what and when I use. Thanks.

Small spring clamp on the shaft, behind or in front of the lights mount depending on tilt?

Or

Rubber band wound around the shaft? Bulldog clip? Duct tape? (my fix everything)

A small binder clip...

Bulldog clips from he Range proved up be an absolute waste of time. You do have to realise a proper large umbrella is close to 2kg in weight.
Collar may be worth a go if it can have a thumbscrew because this needs to be adjustable on the fly without any tools.
I am leaning towards drilling the bloody flash bracket. It should have been done by the China

Regarding the collar, you could replace the grub screw with a wing screw.

I've not seen the bracket, but if it's thin, the alloy/plastic may not stand up to a thumb screw for long.