I just needed to know before I offered any advice if you were trying to do it differently on purpose Yah never know, right?

The actual weights will of course depend on what is best for you, and that will change as you get stronger and as you perfect your form.

For the specific exercises, say the chest area your workout would looke something like:

Chest press (compound move should be first exercise)
12 reps 15 lbs.
10 reps 18 lbs.
8 reps 25 lbs.
6 reps 30 lbs.
12 reps 18 lbs.
Fly (isolating exercise) for second move
12 reps at 10 lbs

Your set of 6 reps should be approx 80% of your 1RM
Your set of 8 reps should be approx 75% of your 1RM
Your set of 10 reps should be approx 70% of your 1RM
Your set of 12 reps should be approx 65-60% of your 1RM (this is for your initial set of 12, your 'warm up' set).

For your second exercise I would advise going with 70-75% of your IRM - it's all going to depend on how fatigued your muscles are at this point. As you get stronger this weight will also increase. Remember, this is the exercise where you reach positive failure (the inability to complete another rep with correct form).

So taking your workout it would look like this:

SHOULDERS :
seated db press: 12 R ~ 10#
seated db press: 10 R ~15#
seated db press: 8 R ~ 20#
seated db press: 6 R ~ 25#
seated db press: 12 R ~ 20#
side raises: 12 R ~ 10# Failure

BACK :
wide grip pulldowns: 12 R ~ 40# (need to up starting weight)
wide grip pulldowns: 10 R ~ 45#
wide grip pulldowns: 8 R ~ 50# (will start ~ 40# next time)
wide grip pulldowns: 6 R ~ 55#
wide grip pulldowns: 12 R ~ 45#
rev grip pulldowns: 12 R ~ 45# Failure

Etc, etc.

You want a compound move for that primary exercise and an isolating one for the second. The idea is you work that muscle and the helpers hard for the first 5 sets, then with the last set you finish off the main muslce you're targetting with an isolating exercise.

If you have a look through the first two pages of mnokat's (kate) and pbach's (pam) Journals you can see a few comments on how to switch these compound and isolating exercises around for a more effective workout.

Cheers,
Nat