it works all ways--front first, back first, or front on dl day. In general I agree with doing what you want to focus on first, then finishing with the "back burner" variation.
I have really enjoyed doing the continuous ramp from front squat to back squat though. I think this has certain benefits to it, namely that it gets your upper back nice and tight. If I'm doing a big front squat training cycle, then I'll go up all the way in front squat first and beat the crap out of it, then do a few sets of low volume back squat work for additional overload. For example, hit 400 on front and then do 225 for couple sets of 20 on back squat (volume boost), or do 450 or 500 or something on back squat for additional intensity training (since you're so tired naturally your back squat won't be as big as normal...but it will still recruit lots of motor units and help regardless)
If I am doing back squat, then I will warm-up with front squats instead of back squats because it gets my upper back and abs firing faster and leads to better tightness for me. Doing that I'll only go up to a moderate front squat weight--something I can dominate and accelerate without fatiguing--then switch to back squat to continue the work-up to a max or top set before weights get difficult. Personally that is usually something in the range of 65-70% 1rm front squat.
I currently squat narrow stance olympic style however, so it does depend on style of back squat.