I would disagree, but it sounds like it works well for your situation, especially if you don't live on site.  I will disagree on the acidosis.  Cattle don't regulate intake very well, and especially in winter with weather constantly changing they are constantly overfilling drving them to acidosis, then it takes them a few days to recover in time for the next front to move through.  If you could measure grain intake and hay intake every 12 hours, It'd really surprise you how imbalanced there intake is day to day.  Nothing beats a tmr in the bunk 2-3 times per day.  Free choice hay and finishing cattle are very contradictive.