I will tell you that lights definately frighten flathead.
I have actually used spotlights to steer hooked
flathead away from brush while my partner
fought them.
You do not have to just blindly believe me though.
The next time you hook a big flathead, reel it up
close and put a light on it just before you intend
to net it. The flatheads reaction to the light should
convince you if it is afraid of lights or not. :

:
Actually I have selected flathead spots across
a bay from a group of catmen using lanterns
and making quite a bit of noise. Any flathead
feeding moved away from their bank and to
mine :shock:
I could definately tell if their group caught a
channel cat because the excitement and noise
level went up. Although they didn't catch a
flathead I caught several. My conclusion was
that the flathead seemed to be acting more
natural on my side. It could be that for several
nights none of the the loud bunch got "lucky"
and I got "lucky" pretty consistently.
The best way to find what works best where
you fish is to keep trying things till you get
good results. Pattern the fish and once you
understand enough of the puzzle you will catch fish.
As far as how close you must fish to structure, this
depends on the mood of the fish. The more active
the fish are, the farther you can set your baits from
structure. Mike found out last year that if you put
a bait too close to an innactive flathead he
will attack it. I haven't found a way to determine
how active fish are other than by fishing.
Flathead are very frustrating because even proven
methods go through periods when the fish don't
cooperate.