I think you've gotten some good ideas. I share this just to give perspective. I had little idea what real poker was until I met a pro player in 1981 who taught me how poker really worked and how to learn to improve. He shared 3 rules about buy-ins that have stuck with me.
Rule 1 In a limit game, the minimum he'd buy in for was 40x the ante (I'd never heard of blinds back then and I don't remember him bringing them up, but maybe he did), but he preferred at least 60x. Translate that into $.25/.50 with say a $1 limit, and you are talking $60 min.
Rule 2 In a no limit game, his minimum was 200x, and he preferred 300x. Translate that into $.25/.50, and you are talking $150 min. Double that for $.50/1 to $300. To me a $20 buy-in is no more than a $.05/.10 game. If you have players willing to put way more up than I'm willing to, I'm just going to concede that's the wrong game for me and not play.
He explained that anything less limited your ability to really play and profit, which was to him the only reason to play. He didn't believe in gambling and once he explained what that meant, I got he wasn't going to take risks where the odds were stacked against him.
Rule 3 Whatever he was told was the max buy-in, he'd bring at least 2x, and usually 3x that amount (for limit or no-limit). He shared a story of flying to a game after being told the max buy was $10K. He took $30K. When he sat down, 2 players were allowed to buy in for $50K. Instead of playing, he left. It may have been because he was misled, or the rules were changed, but I always thought it was because he didn't want to play against 2 chip stacks in NL that started bigger than he could possibly match. I didn't understand this beyond he saw it as a severe disadvantage against good players. He wanted to at least be able to be competitive against the players. If I could talk to him now, I'd know enough more to clarify this point; maybe I misunderstood the real issue he had.
Most of the cash games I hear about around here are so far under these standards, I won't even play in them.
As for what casinos allow, be careful. Casinos do things that make the casino money, not what makes a good game or smart money management for players. As long as they can get people in, they will do what is in their own best interest. They will only adjust when it's not profitable for them. That's not to say that we should ignore what casinos do. Just be aware their goals start with them and not the players.
Home poker is totally different. It's all about the players. I don't want to duplicate what casinos do. I want a game that is more attractive to players than a casino game.
In the early '80s, I played in a game where we had 4 regulars, and 3 semi-regulars. We could usually get 5 a night. One guy was a consistent loser and considered dropping out of the game. To save the game, which was for me both fun a profitable but not big money, I gave him a couple of tips, and twice folded the winning hand to him to keep him in the game. It cost me a little money those nights, but it kept him in the game for several more months. When he dropped out due to losses, it seriously affected our game. We lost a regular, but about that time picked up another semi-regular. After that we averaged 4 players. I made a little less, but won slightly more often. If I could have, I'd have given more some additional pots to keep him in the game since 5 players was more profitable than 4 players. If you see poker as one lifetime session, you plan strategically and sometimes make a short-term sacrifice. That is playing to win, but it's weird if you think of each session on its own. Extracting the maximum amount from a game can destroy it. Sometimes there is a delicate balance.