I've got several sets of 1x2x3 blocks of various qualities, some 'perfect' exact size and others a little undersize after being ground square. It's a neat idea which I had forgotten about as I don't use them very often.
video was too long but was for 'beginners' so I guess he had to explain why he was doing things?
I would have made some double diameter studs as well for the times you want blocks locked together in a larger size (oh, I already did
)
Various length studs are easy to make from ordinary bolts, cut the head, off turn shank to diameter and thread it. (heads are usually forged so much tougher than shanks)