I have tried the reamer solution. I bought a piloted adjustable reamer (size K IIRC), made a target piece to accept the pilot, and then tried it. It was very hard to start reaming and impossible to do it without chatter & grooves. So I decided that I'd bought a crappy reamer & bought a better one. The results were still very poor.
After months of wasting time (& ruining bushings) I decided to learn to do it on my buddy's mill. Once I figured out the setup & oversized a few bushings, I find that it's a 1 hour job to size the bush just like Ade in the youtube video. Doing it without a DRO would not be much fun.
I'm just too impatient and am done with trying to ream a timing side bush. Milling is easier and you'll learn if you timing side is Concentric
to the drive side.