Here's a basic amp question for all the experts here.

Say a stereo amp is rated 100wpc. It has 2 speaker out posts, though,
and a switch for "Speaker A, Speaker B" (or both). it's a 2channel
amp so if hooked up to 2 speakers, does it then power at 50wpc for all
4 speakers or is it in parallel so still powers at 100wpc?

Also, i understand that most people say that speakers sound better
when bi-wired. What is the best way to bi-wire? My B&W801s have 2
sets of speakers posts with a shunt that connects them. I am
connecting my amp to one set and it is concurrently powering both
drivers. I have seen bi-wire cable that goes from 1 set of speaker
terminals on an amp and splits to 2 sets of speaker connectors. it
had a writeup regarding the type of wire for each and how some
"frequency" transmits better across one of the conductors than others.

SO is it best to (a) cable from amp to speakers and use the speakers'
shunt to bi-wire (b) use bi-wire cabling (c) connect separate cable
from each of the amp's speaker out terminals. Does getting a separate
identical amp and wiring that to the separate driver offer any
performance upgrade to (a-c)?

thx in advance
-goro-