As another poster said...trimix dose is very personal. And it varies alot. I was down to 0.025 mL, with what appears to be a standard protocol mix... and that was too much for me. I had the pain and extended wood, even at that dose and watered down, literally, by 50% with a saline solution. My next step would have been bimix, but orals like levitra were starting to work.
It was, according to my doc, the alprostadil that was the problem for the pain. That's pretty much the most active ingredient in caverject and trimix, IMO. Maybe ask your doc about bimix.
Good Luck