Other options, to keep the sweetness levels of the original ratio, are to swap a fraction of Campari with Aperol, or just build everything over cubed ice in a glass to accelerate dilution.
Replacing all of the Campari with Aperol does not, in my opinion, yield a Negroni. The result is incredibly tame with little bite.
Use a larger coupe glass than normal. The recipe does not dictate egg size. Larger eggs may need a extra dash of brandy. I could never get a flip to fit into a Nick and Nora glass, so it doesn't seem unusual to need a slight glassware upgrade.