I just wanted to chime in with my experience. I would have had my Oring project done if I had not snapped the plastic piece on top of the #1 injector! So not I have to buy (and I'm waiting for) a whole fuel injector install kit for just one piece.
I do want to mention that the inner O ring and the outer O ring are not the same size. I was able to find the inner one at my local Napa. The outer O ring came from an Oring kit from my local autozone. I used one with the following size as suggested in other posts: 5/8 ID, 13/16 OD, 3/32 width.
My only concern is that when I re-assembled the unit, it was a tight fit. even though i tightened the large brass nut where the filter screws on to, the protruding electrical connector is cocked a little. I'm hoping I tightened it enough to keep it from leaking. I'll let ya'll know when my injector install kit arrives in 3 days and I can get back on the road.
thanks