As far as why not 24" bulbs, basically because of cost. I did mention it as another option, or we can call it "Option B'".
"Option 'C '" which would be a change in the overall dimensions is also feasible but I suspect the reason I was told use 3' wide lighting is because of appearance, a light wider than the table may appear "out of place" and it would be putting out light well past the playing surface. I don't know if this may create a potential shadowing issue but I can understand that being a result. If I was going to go to a larger dimension I think I would just go 4 x 8 and be done with it, so at least the light was over sized in both directions.
Thanks for the comments, as I am sure since 8' tables are quite common in homes (why couldn't I have had another 2' x 2' room, id be on a 9er!) that I won't be the only one who will benefit from the discussion