I think the best solution would be to brush first, then floss, then use a mouthwash. The brushing cleans what it can get to then the floss removes what the brush couldn't, then the mouthwash rinses off the detritus that was in between your teeth but, thanks to the floss, has now been deposited on the areas that your brush can get to, but there's no point brushing a second time as excess brushing can wear away your enamel.