It certainly won’t hurt, unless you’re trying to fly manually in forward flight. Then it might be very sensitive to your pitch inputs. I just extended the elevons behind the motors on my tailsitter as well, and hopefully I’ll be able to test-fly it today. Pitch authority in a hover and in transition will depend on a lot of factors (C.G. location, center of pressure movement at various angles of attack, prop wash velocity over the control surfaces, ect.) other than elevon chord, but I haven’t read about anyone who has designed a tailsitter with too much pitch authority!
Are you going to add the wingtips to your Caipirinha?