I'm doing the same thing right now; work out mon-fri with the weekends off. What i do is I have a four day split, and the use the fith day for a lagging body part(s). So if chest is lagging it would look like this:
Mon-Chest Bi
Tue-Legs
Wed-Shoulders Tri
Thu-Back Traps
Fri-Hit chest again, and maybe bis
Also alternate forearms and calves every other workout. But this is just my opinion, best advice would be tinker with your own ideas for a few weeks and see what works best for you, as we are all different.