I agree with the two recommendations you made for long term Bitcoin investment sustainability. Another thing I would like to add is that when you implement your own strategy for long term management it will be consistent with your daily life and expenses how you organize your investments and grow your Bitcoin holdings. In the long term effort you will encounter many problems and sometimes you may get upset and feel pressured to withdraw your valuable holdings. What should be the amount of emergency fund, how many months it is safe for you and your investments, your income and discretionary funds these are important things to decide for yourself.
That is true, keeping your own strategy is more important than all of this. Most of the time people say have 6 months of salary in your bank account for emergency and that should be enough. I mean unless something HUGE Happens, then 6 month salary should be enough. In this case, that means, you should just save 10% to 25% of your salary, for a short period of time.
So, let's assume that you make 1000 dollars, that means 6000 dollars is enough to save, so if you keep lets say 150 dollars a month to save, then in 40 months you have enough. Now, that may "sound" a lot, but humans live around 70+ years, not all of us of course, but that is the average age, and giving up just 4 years of that, in return of having decades easier, I would say it's a good idea. After you reach that? You put all your savings into investment. That is the suggestion at least.