Question 2: BRM?
This question is very player depended. First of all whats your variance? How many Tables do you play? Do you fokus more ono Rakeback or on Winnings?
But leaving all these Questions behind there is one answere.
Whats your monthly expesces? Make sure you can afford taking off a month or two or even more important losing 2-3 month i a row.
Say you play NL100 and need to cash out 1500$ per month. you wont be very safe with a 10k Bankroll. even 20k is very close.
It all depends on your midset. But i´d say as a professional Pokerplayer you should run 200 Stacks BRM if you playing NL200 or NL100. as son as you move up you can allways go down and make aggressive shots wenn you hit the, lets say 50k$ mark. It all depends on your winrate, your monthly expenses and your mindset.
As a recreational no queston. 10-15 Stacks and a solid up-/downmoving scedule. And plan to move up or down a few limits within a day.
Theory/Play ratio:
Everyone should be able to estimate rougly how quick he can learn. If your on the slower side, u probably want 1-2 hrs of therorie for every 5 hrs you grind. if your very quick and able to bring in your own thoughts you may want to learn only 1 hr for every 5 hrs grind.
I think all these question are VERY playerdepended. Imo you cant argue alot about that without a certain playerprofile.