Sorcerer has even less of a problem with that. Sorc has maximum of 1400 casting speed so he does not drain MP as fast as Spellsinger. Further more, Sorc has Body to Mind level 1 so he can use this skill when in great need of MP. It is not as effective as Body to Mind level 5 but it helps nevertheless. As for Tips 1, 3 and 4 – they apply for any and all characters. 🙂
It is not that you do not understand, it is that you do not even question.