i was talking to this guy and he said that fender usually have bright pick ups, thats why 0.9 strings would sound better than .10 ??

i have a strat with 2 single and one di marzio hum. pickup
with .10 strings.....
cus im hving a bit of sound trouble where i get too much gain, and bass and bright treble.....
any comments from the techs ??