Bearing block wise, I personally use a set of measuring spoons or a shot glass with some duck tape around it to prevent shattering. But if going old school and want to use wood, anything harder than the spindle! Use your thumb nail and poke it in the wood for your drill, then do the same for a few others. Whichever is the hardest to poke your nail in you can use! (Not an exact science )
It's a nice idea to use something like the measuring spoons, and I saw a nice bearing block (I think it was an MCQ bushcraft video) which was a piece of Antler with a 15mm copper pipe end cap embedded in it.
But the reason I want to learn this skill is in case I need to use it as I have no other means of making fire. So while it might be beneficial when learning the skill, I don't want to be dependant on it.
J