I’ve uploaded a few:
I’ve got all my streams locally recorded in 4K but I’ve not done much with them.
on the display size its only worth doing in my view if your local 4K display is >60" you can fit the playfield in at full rotated 1080p but unless you have a decent sized screen IMO it doesn’t look that different on a small screen from a distance but thats my eyeballs others might be different 
the other downside is some browsers YouTube won’t give you a 4K option.
Neil.