Don't know much about racing but my boat had a code 0 and a genoa. If there is wind enough there is no problem in setting up the spinnaker wit the genoa because it would fill well, the forces will be less and it would be faster and easier to trim. But if the wind died suddenly and you have very little wind the Genoa can shade the gennaker and make it more difficult to catch wind and more difficult to set.
But normally I do this alone so the easiest way is the way to go for me. With a full crew probably Faster is right and you can overcome any difficulty with more people handling the sail and win a meter or two even with weak wind