I was wondering... what the pros and cons are of certain splits.. (basing it on a 3 or 4 day split.. with each muscle group - once a week)
for example...

at the moment i do
mon. chest/back
wed. biceps/triceps
fri. shoulders/legs

(mainly supersets)

alot of people say about working each muscle, only once a week.. but obviously.. with, say, chest, youre working your triceps aswells.. so really that muscle is being worked (quite heavily) twice that week. so would it be better to put the chest and triceps.. same day? and back and triceps would be another example.

Also second (and last, promise!) question.. is about supersetting..
and to cut it short, whether it should be opposing muscles.. or can it be the same one.. eg. 10 flat bench.. straight onto 10 incline bench.. then repeat.. etc etc etc

or does it just not matter?
any help would be very much appreciated!

Thanks,
Tye