It might be that you have to make sure that the spark is right in line with the flow of the gas. I ran into a similar problem last weekend with my Camp Chef stove. It has 3 of the round burners and I could see the spark going from the electrode to the burner. Thing wouldn't light. I wiggled the electrode so that the spark went right over one of the holes in the burner and Whoomp, it it lit right up. For that setup, just having the spark in close proximity wasn't enough.
Thinking about it now, this might be why Weber gassers have the rectangular gas collection box that the electrode runs into. Instead of needing pinpoint accuracy, that box pools the gas so that the spark will ignite it.