I think it is in fact a bit misleading, but in truth, the point gap is likely to be reasonably close which is probably why he gets (I assume) good results. It is a result of the fairly limited adjustment range when all the parts are new and properly assembled. And, the performance requirement is fairly easy - compare to a V-8 car engine with a single set of points - It may redline at half the revs, but has to fire 8 times as often!
And yes, adjust the gap(s), then the timing for both cylinders with the single timing plate. And as noted in the manual, you can go the extra mile by adjusting the other set of points afterwards to get that cylinder perfect as well if needed.
If you have a strobe light, it is easier, and often more accurate (depending on your static timing setting skills).