So with the slightest of head pressure, we are at 47+ l/h. Seems like Rossi's 60 l/h is just a short skip and a hop from here. I don't want to minimize all of your efforts Alan F. by highlighting this fact, but it does appear to be the case.
Mr. Rossi never suggested 60 L/h as far as I know. In his deposition as the representative for Leonardo he said he thought the rate was near 100 L/h. An anonymous contributor then popped up on Rossi's blog (as they do just when he needs them), and said that based on personal experience the figure was 90 L/h. Then in Mats Lewan's interview, Mr Rossi said 72 L/h.
I think that the 60 L/h figure comes from taking Penon's figure of 36,000 L/day and dividing by 24 hours and then again by 24 pumps. This gives 62.5 L/h as the per pump rate needed to achieve the reported daily flow if all 24 pumps on the Big Frankies are working. On some days, however, Penon reported the usual 36,000 L/day pumped even though only 3 Big Frankies were in operation (for instance on Oct 14, 2015). This leaves only 18 pumps, and so on days like this each remaining pump must achieve a pump rate of 83.3 L/h.