I have only done IV ozone once. Though the person administering it was doing it a lot faster than the recommendations I have read for zone administration from German medical doctors. He injected about 90cc of ozone before I started feeling the effects. I did alright for about 30 minutes, then it hit me pretty hard. I had to lay down for about 20 minutes then I was fine after that.
I have never experienced this effect from rectal insufflation, so I think I will stick to the insufflation.
Come to think of it I wonder how much of the feeling in the lungs was from the injection of the oxygen component. What is actually being injected is only a small fraction of ozone. The vast majority is pure oxygen. That is a lot of oxygen to inject in to a blood vessel.