Gluten-free Carrot Cake batter mixed with normal Carrot Cake batter
Well, it went quite well. The flavour was really nice (I guess corn flour did not change the overall carrot cake flavour that much), and the texture (which was what I was most scared of) was as a normal carrot cake. 

The timing in the oven was more or less the same (as I used the same mold several times, I did not measure the grams I was pouring). So my conclusion (not scientifically tested) is that it did not change, or if it did, it was minimal. 

Just to state constancy, the final mix was more or less: 


1/4 of all the mix: Normal Carrot Cake batter (wheat flour)
3/4 of all the mix: Gluten-free Carrot Cake batter (corn flour).


I also mixed some blue coloring but in the end it turned out green, but it did not change the flavour nor texture!

Final results: As I needed to transport the cake for 30 minutes by car, the frosting went a bit ugly, and in the fridge later, it was hard to re-shape it properly. But flavour was good.