I'm a bit confused as to what H can do to match things up on the port side other than removing the sharks mouth and moving it up a bit to match the gap that he has on the starboard side? Straight piece of tape looks to be aligned pretty close on both side to my eye? Maybe I need my glasses?
Maybe the angle of the straight strip of tape is off. Might serve you well to tear of a longer piece of tape and stick it the entire length of the front fuselage, like in the picture with the red line on the starboard side? Hope that makes some sense.
I think your getting too frustrated on this build Harrison, after all it is just a model airplane. May do you well to step away from it for a few days and come back fresh.