I find the 3mm perfect for bass as theres no 'lag' when plucking especially if its a quick down and up stroke i feel that using a .7 or .8 pick has a slight bit of give in it before it releases the string, maybe im just weired but i feel like i can pluck quicker using a fat pick, if youve never tried one give one a go, i was skeptical at first but now i wont go back.