The real thing is an E, it's made for the C.
The C4 had about 1100HP engines. The D had about 50 HP or so more, but was made to allow under wing ferry tanks (not like the 109 DTs that the G-series has, big things with vertical fins on them). The E had 1200hp engines and was basically identical to the C/D but with wing DTs (still big ones with vertical fins).
The G had 1400hp engines. The G series has 2x30mm and 2x30mm. A few Gs had 7mms but not many.
So Even though "E" is closer to "G", it was much closer to a C4 than it was to a G2, in performance and firepower. Think of it as a 109E4 109 E7 109F2 series. The E7 is much closer to the E4 than it is to the F2.
Same for 110C4 110E1 110G2. So I had no qualms about making it a C4 skin.
EDIT: I bring up the 109 comparison because the C4 had DB601A engines and the 110E had DB601N engines, similar to the 109E4 having 601As and the E7 having 601Ns