The Ellis products are neat,but need to be of the appropriate size,so you would need a stock of the sizes you may use.
You can get good quality tie-wraps,with an eyed end,which can be used for many purposes,and in the application discussed here,can be "stacked",by reversing one tie,and fixing both with one screw.
They are available in all colours,and nothing screams "----",like all conductors secured by a colour appropriate fixing.
I did a friends, like this,and a few years later,he said he had meter swap due,and would i turn up,to ensure no sneaky smart telemetry was installed...
We were having a brew,whilst the meter dude set up,and i asked if everything was ok in there...he replied "who ever did this,was proper OCD!"
Needless to say,much mirth was had...