When I was using Caverject (6-7 years ago?) it came in an injector where you could set the dose before using. I would have to look at it to remember what my dose was but I do know it wasn't the highest setting and I never experimented going higher than the doc recommended. Even at the lower dose (in the middle of the setting IIRC) I experienced some pretty achy erections. Maybe the curvature could have been caused by scar tissue from injecting in the same spot all the time or long term usage. Or possibly too high a dosage?
I didn't stick with it after the relationship I was in ended and pretty much stuck with the pills after that
It's nice to know it's an option if ever needed though. It definitely worked for me, I could punch holes in drywall I would get so hard. The doc who prescribed it for me is the one who told me I had some venous leakage. I can get it up often but maintaining is the problem.