think you should be fine. two days off should help get you the rest you need. i read an article recently (and i hope this applies to you) that branch warren did chest twice a week because it was at one time his weak point. if i was doing that program though, i would do chest monday and thursday - 3 and 4 days off respectively, vs the 5 and 2 that you've got going on. otherwise, don't see why not. though i am curious why if you're doing back/bi's pairing you wouldn't also do chest/tri's. just a thought. anyways, hope this helps.