YIKES,
that looks bad @ss.
remember,
when you are used to driving your amps' gains at certain levels,
to get your 'sound',
it will change if you now can drive the output section of the amp as hard as it was originally intended..
all you gain structures will change,
all your 'tone' settings will change.
to me, the simplest thing to do, is throw all the old settings out the door.
set up everything based on 'halfway', or 5 out of ten, on everything to start.
move from there.
usually hiss and noise is going to come from your first gain stages,
so you may simply find that moving your first preamp tube down the line in terms of gain, solves most of it.