i know wrong board...
but has anyone ever trained biceps before back???
to better isolate the back or is that just bull shit???
I depends what u want to achieve. are you biceps weak and need bringing up?
are you very strong and hoping to bring down the overall weight by pre-exhausting?
a lot of guys, like Jason for example, often pre-exhuast the delts by doing side laterals before presses.
It does not necessarily isolate the back, if the biceps are tired it might actually mean u don't stimulate the lats as much as you would have if they fresh.
try doing some pulldowns but don't sit on the seat; sit on the floor!!