please list out exercises, how many sets, how many reps, at what percentage of max for the sets, and any progression plan for your workout please. without that we cant answer your question well at all. this does remind me of a post i once saw. it is like asking whether a blonde or a brunette is hotter without showing pics of either and no other information on height, weight, etc.
you are working chest twice and back once a week. if the volume and intensity are the same each workout then i would reverse that and do back twice as much. especially with the back having so many muscles (traps, spinal erectors, lats, etc) when compared to the chest (pecs). thats one thing to change with the tiny bit of information you have given us.