Do I need any int gear/base int to wash a bm to 5.8k hp at 155? Will washing out job advance MP be enough?
You should have around 4400 or 4500 hp at this lvl so you need to wash the rest (should be around 900 mp to turn into hp). You get something like 150-200 mp for each job advancement (except 1st job) so you would need to get the remaining mp from int (unless you have equips with hp like valentine/zombie army ring and others)