Even though the butyl tape is more commonly recommended for roofs with a 2/12 pitch or less, I'd say go ahead and use it for your 4/12 pitch too. It's always better to be extra cautious when it comes to preventing leaks.
I believe everyone should have a kind of safety cushion that will not leave him without money in case of trouble like unemployment or an unexpected rise in the price of necessities, etc. When I accumulated enough money in such a "cushion," I did not start taking money from there for my regular...