And if they happen to be "end cogs", it's even more minimal.

Back in my "poorer" days, I used a bunch of 7 speed cogs and thinned the spacers to equal 8 speed spacing.
I had index shifting, so I wasn't too concerned about it being "perfect".
Last summer I bought a "real" 8 speed bike and tried my home brew cassette (13-21). It worked much better than the 11-32 that was on it!