I already converted a Bird. It didn't have any security screws and was simple to find the mono to replace the paywall.
Unfortunately Birdy doesn't have a contract for SF and they have been difficult to find lately.
Scoot and Skip I think are the only shops contracted with the city of SF.
Scoot scooters are pretty nice. They also have a lot of extra security. Also its difficult to find replacement parts as Scoot is just a client of a Chinese maker that sells an all in one package for ride shares. You get the custom color, your brand name on all the electronics and probably you need to be a customer in order to get the replacement parts.
That's why I am here, to network with others and learn.