Well first, those two fives which are equal distance from the fulcrum (pin/roller support) will have no overall effect on the load that you are lifting as they provide countering moment forces on the bar (they would simply place more weight on the fulcrum).
Assuming the bar is an evenly distributed 45lbs (close enough, slightly different due to the sleeve weight) and it is a 7.2' (86.4") bar, here is the approximate weight distribution if it was just the empty bar:
Then if you just add the weight that you add to the end of the bar, you will get close (this would be assuming the weight was directly over your hand).
The weight will change slightly depending on where you are in the arc as well, since the force vectors start changing due to gravity.
To summarize, and for simplicity, I would just take it as 20lbs + plate loading per hand and call 'er a day.
I hope I didn't just confuse you more....