Usually fast acting is 4 hours. I am pretty normal, but it varies from person to person.
I would check hourly on a "normal" (ha ha) day and see the rise and fall.
Basal testing is not big here, and I do not do it often, but when starting out it can really help you see the levels--record and look.
Usually, in my mind, the more insulin you require, the less likely that you are more sensitive. When I was first diagnosed in 1962, I took over 150 units per day (I know, different time, different insulin) but I now dose about 12 units of novolog per day. It can all change.....