No account required to view that (well, I didn't have to sign in anyway). And it is a nicely made tool. I'd expect there to an Edwardian version in some long established bike shop, but I suppose it's mostly an aluminium seatpost problem so not that old.
A set of adjustable reamers will do it. Eventually.
High volume air tools generally need: enough pressure/volume in the tank, and enough flow in the hose - a skinny hose can throttle a tool, it can be better to pull and release the trigger frequently rather than just holding it on constantly, so at least the first ugga-dugga gets full pressure.