I’ve got a couple of devices for installing tubeless plugs, but one of my favorites is the Cigar Tool Plug Kit and CO2 Head from Crank Bros.
The kit comes with a knurled aluminum cap into which you can thread a CO2 cartridge. The plug tool is incorporated into the cap so when a CO2 cartridge is threaded in, it becomes easier to manipulate, without the downside of permanently making the tool larger.
It includes a CO2 adapter so that you don’t have to go looking elsewhere for it. They include five tire plugs and the plugs are rated to 40 psi. This last detail isn’t something I’d normally disregard, but I didn’t check the specs before cutting one of the plugs in half and using it to plug a 28mm tire, which I then pumped up to 60 psi. It has held without fail. I don’t blame Crank Bros. for posting what now seems to be a relatively conservative max pressure, because lawyers, but I’ve now put enough miles on the plugs that I’m confident reporting that 60 psi is not an issue.
The Cigar Tool Plug Kit goes for $29.99, making it more affordable than some of the options out there. A five-plug refill kit goes for $4.99, which is so inexpensive as to make my cutting one in half absolutely silly. The reason I cut them in half with road tires is just to make them easier to manage, but I’m not sure that helped in any significant way; it did feel less wasteful, but talking about waste with regard to tubeless plugs lacks a certain sense of proportion on deeper consideration; even so, I’m likely to continue doing that with road tires.
The Cigar Tool Plug Kit comes with a bracket so that it can be mounted below a water bottle cage if seat pack capacity is at a premium.
Final thought: Road tubeless is a go.