Thanks for the kind words azforlife!
I think the thing to always remember with BRM (bankroll management for those reading this that don't know), is that even the best players in the world regularly have to move down.
Because when you are taking a shot, there is always a large element of short term luck involved. Even if you found a really good game against some rec players where you have a large edge, if they cooler you in a couple big hands (KK into AA etc.), that's it for you and you need to move back down.
So with regards to being disciplined with taking shots, I think the best thing to remember is that it is about moving both up and down. Most people just focus on the up part. You should be prepared to fail again and again when taking shots in poker.
With regards to what amount to buy-in for, I already touched on that a bit above in another question, but I have always been a full stack player, 100bb. This doesn't mean that I think buying in short can't work for some people in some situations, it's just not my area of expertise.
Although I did actually even write a big article on that lol. My guide to optimal 50bb poker strategy:
https://www.blackrain79.com/2017/11/50bb-poker-strategy.html
I always recommend for people to learn full stack at some point at least though because if your aim is to be the best player at the table each time you sit down to play, then this is how you are going to exercise your edge to the fullest.