active or passive pickups when designing

[lorddracula_me]

hi, i was wondering, do you use mostly passive pickups to design, and what happens if for example you design a full metal distortion with a passive guitar, but plug in an active one later, how do you go around making the range of the gain very big,

and also, making it behave well, i.e. when you turn the pot, the gain to gradually increase, not to boost up in the 1st quarter turn, and then stay the same for the rest

thanks,
boris