Again if it helps, correcting the dihedral. I hadn't considered this until I started reading then karked myself...but its actually easier than you think particularly as the cut line is effectively marked just outboard of the inner engine. By rights I suppose you should correct the "hang" of the outers but the few who did this didn't seem to think it notices...neither do I. Not sure why so many manufacturers miss it but chances are they used the same references (or moulds).
If you don't cut through the TE and LE they will distort, then fill the lower chordwise cut with plastic card (thin, trial and error) and weld with tamiya extra thin. Easier than I expected and there are various descriptions online
5 attached images. Click to enlarge.