We had an old thread about this. Depends on the coin type (modern stuff and SE), coin tier (value of coin). TPGS's are sweat mills. I should guess that if you could not grade 3-400 typical vintage coins (1900's +) of average value per day you might get talked to. I'll bet a better guess is closer to 500. The modern guys may do well over 2000 (that's only two monster boxes) and I'm guessing that's a low number. Someone should ask the graders at the Summer Seminar one evening at the "Lounge."
You can come up with an average based on their numbers graded counter and what it changes on an average day but it varies depending on the coin. Run of the mill easy coins and moderns they can blow through quickly, others will require more time. Obviously a bust dollar or a variety attribution will get more time than the ASEs in monster boxes.