I guess it’s not dangerous if you are taking an injection every two hours or more often. I just think that you will not get the same picture as you will when a pump is delivering 0.05 units every five minutes. We were able to nail down my basal rates pretty quickly with a some fasting basal tests once I started on the pump. There are formulas to calculate starting rates based on the amount of basal insulin that you took previously.
Plus your body reacts differently when you are fasting for days, I think. The “fasting” basal tests means skipping ONE meal and testing your basal rate. I don’t normally fast all day.
If you are really sure that you will never go more than 3 hours without an injection, then you should be OK, but I think that you would figure things out quickly once you read pumping insulin and start on your pump.
I guess I’m just afraid that you will become exhausted and fall asleep for 6 hours and wake up in DKA. That’s why I would not do this.