Hello, I have a question, I just bought a Makita 5Ah battery twin pack for £100 from my friend, and I have the opportunity to buy another two of these for £220 (4x 5.0ah batteries) or I can buy 3x 6.0ah batteries for the £220 - which deal pays better? Will I do more on 4x 5ah batteries or on 3x 6ah ...