I found it doable, but I would ask first-timers if they have ever pulled and pressed bearings before. And more than once. And, do they know just how stuck a taper can be (man, my output flange did not want to come off, destroyed my homemade tool). And do they know their way around the measuring bit.
Otherwise, crack into it. The worst that happens is you feel overwhelmed, and then you ship it off to whoever. Give yourself plenty of time, of course.
The nuanced ability to interpret various things that a first-timer lacks are certainly real. Just how much wear here and there can be ignored, and how much can't, etc. And then the shimming. Experienced rebuilders will have proven practices, and preferred targets for the shimming that I just don't. Proof in that pudding awaits.
As I said my opinion on the measuring is that mold-a-gauge is the way to go. I milled up a plate, checked everything for flatness with a good straightedge (and I know that's not just a ruler). I have good, maybe even very good measuring tools. I was pretty confident in the results, but a little squeamish about the variation point to point around a single bearing. I wanted to contrast that with mold a gauge just out of scientific curiosity. The results were different. The "measured" gap was a bit smaller all around, the mold a gauge gap larger. Not way off, but significant, and not perfectly consistent. So, I would have shimmed them looser if going by the "measurement" technique. My result might still have been fine. As SS said, plenty of leeway I guess.
The compelling thing was just how perfectly the mold a gauge worked. Here we're these perfect hard little plastic rings that had been filling the very gap I was measuring. They obviously flowed all over as they were squeezed, and this is why I think solder is flawed. If your gap is 1.5mm, and you have 2mm solder, well, sure, you are going to get a good result. But if your gap is slightly smaller, that solder will reach a point where it will start distorting the cover, and I believe it would be easy to miss that. You would have to have very good touch when tightening the cover to feel that the solder had reached its plastic limit.
In my case, one shaft had much less a gap than the other two. Solder would have been fine for two shafts, and the third would have distorted the cover, then distorting all three measurements. Only mold a gauge will allow measurements from virtually zero all the way up with no distortion.
Now, it's possible that this stuff (and as soon as I saw it I thought, i know what this is, of course, why didn't I think of that! But you should order from Cycle Works for the valuable instructions) this stuff might have some wildly large thermal expansion coefficient. That would be a problem, but I bet it doesn't, and the error would not be large anyway.
The only downside is the oven. I have an electric kiln, so it was easy. But think of all the tools, plates and whatnot that you don't need. YMMV