Re: Octaver and EQ placement....
Some of this depends upon the sound you are after-
When dealing with crunch and EQ, EQ in front of the preamp doesn't change EQ as much as it changes the character of the crunch tone- I've been able to get sounds that break up in the low end but remain almost clean on the highend- (this is even easier to do wiht 2 amps)
After the preamp, it works much more like EQ in the studio, ie let's scoop the mids or increase the low end-
Definately worth trying because the differnce is pretty extreme