Your min bet is the least you can get away with at any given moment and might vary depending on table limits, desired spread, rules, and any number of other factors so basing risk of ruin and bankroll requirements on your minimum bet is not a good idea. Basing it on your max bet is only a good idea if you use the same max bet at the same edge for all games which is also not a good idea as you're seldom going to get more than a 2% edge on shoes, but frequently get 5%+ on well cut pitch games and even 8%+ on a good single decker so if you cap your top bet at 2% you're leaving a ton of money on the table.

Decide what risk of ruin (Kelly Fraction) you want to use and apply that to your desired betting unit and see the size bankroll you will need. Conversely you can take your bankroll and apply the appropriate Kelly Fraction and see what betting unit you can get away with. Your betting unit is what you would bet at each 0.5% (if using High-Low) worth of advantage.