Does your oil pressure light come on at idle when it is cold? or just hot?
Pressure is always lower as the oil gets hotter because viscosity drops with heat. If you have a guage what is the reading?
I know on my bb I have over 50psi when it is cold at idle, but once it's good and heated up it goes below 25psi. I wouldn't worry too much about that.

As for the rough idle, you say with a timing light it looks like it bounces all around? But around what range? Sometimes at idle it is tough to see a clear #, but just try and hold it real steady and keep the gun pointed perfectly still. Also, what happens when you rev it? Are you see a good rise in timing as you rev?
Maybe your baseline timing is too low. You need to know what that # is before you can move forward.
Plus, do you have a vacuum advance? That makes a huge difference in idle quality.