It's ok, Peg. I think you gave him 0.1u, which would be 1/4 of the 0.5u line. Let's try 0.25u next time. 0.1u doesn't usually do much with a highdose cat anyway.
Yes, you treat all lows basically the same, using carbs to bring them up. Of course consider where in the cycle it is. A low #at +2 may be more of a concern than a low at the nadir.
For tomorrow, let's see how high he is at +8. I can look for you at 2pm your time again.
Often I saw the most significant results of using R in the next cycle. He's starting lower than he would have if you hadn't used R. Also in cats with iaa the R's action can be longer.
This is all good for gathering data. Just keep an eye out tonight in case you see a delayed response. I don't think he's headed for low numbers, necessarily, I just mean not to assume there can't be more response still from today.