Given that you work 8hr days and all your shifts are daytime starts, I would suck it up and get to the gym before work. I, like many others work 12hr days, 2 days, then 2 nights. I make a point to get to the gym before shift. I feel better and work better. I also don't need to worry about getting it in at the end of the day.
You could also start your training week on Friday. That way you have 2 days in the bag before your work week starts.
Like you said, If this is important, you will get it done. If not, you won't.