@Terry4 - These are rough answers, since I have pretty much removed the exact math from my Afrezza treatment. That, and "it depends" applies across the board for me.
I use roughly a 4u to 16 carb ratio with Afrezza - 4u for 12-24 carbs, and 8u for any in the 28-36 carb range. A typical meal for me varies between 0 units (for say 8 carbs) to 12 units for a high carb meal like pasta.
Sometimes. Lately I have been having a rise around 3pm due to less afternoon exercise opportunities, and in the evening around 8pm due to snaking. Those cost me roughly 12 units over 2-3 hours, in 4 unit corrections. I shoot for 110 bedtime glucose to keep my dawn phenomenon in check. Other times I do not usually need corrections.
A sinlge 4 unit does lowers me about 20 points. One of the things that differs for me is that I do not get the 15 minute lowering effect many do on Afrezza. A small rise will level out in 15 minutes with 4 units, but lowering usually takes about 30-40 minutes before I see the numbers drop significantly. If I do not wait that 30 minutes, and I take another correction, I will bottom out.
I get both 4 and 8u cartridges. When I started Afrezza, I used more 8u ones and found myself overstocked on 4u cartridges. Now that my Tresiba is dialed in where I want it, I find myself using more 4u cartridges. I am considering changing to only 4 unit cartridges as it really isn't a big hassle to double or triple dose if needed.
An example day is today - I have used 10 4-unit cartridges between 8am and now (7pm) - 50% of total (basal+bolus).
I could never keep the tight control I do if it wasn't for my Dexcom.