RE: building chest and back
you seem to train arms and chest twice a week
and shoulders, legs and back once a week.
makes no sense to me.
plus you do chest on a weds then a fri, only one day recovery.
at the minute i have four sessions a week.
Abs after three of the sessions.
some people do:
chest and tris
back and bi's
Also you do three chest exercises and only 2 back exericses.
You could add seated cable row, and bent over row to that.
personally i would bench, before pec deck.
Plus wide arm pull ups are the "daddy" exercise for a Triangular look.