I’ve done tubeless conversion for my F650GS, 990 Adv, and Africa Twin all for just rear. If you can’t change a tube on a 21 inch front tire, you shouldn’t be riding off road anyways. Usually the rear is painful part to repair on the trail.
Previous two bikes I did the method from this link. It worked very well. I attempted the same on my AT, but the way the nipples are raised inside made it very hard to seal. So I purchased the Outex kit from ebay. It’s very easy to install, and once you touch this stuff, you will understand how fool proof it is.
You don’t have to buy the full kit. I gave them the bike model, and they suggested the correct tape width/length from CB1100EX which is the same as the Africa Twin’s rear.