Hope your hot date turned out well!
I haven't used trimix but do use bimix, having a string of failures in my early experiments. After that happened, I used the VED, with constriction (ring), for probably about five times. I needed constriction with the VED -- essential. No surface bleeding, and as far as I could detect no evidence of internal bleeding -- such as unusual swelling at the injection site. Having since heard Dr Catalona's advice, I won't be making a habit of injecting, then pumping.
The fact that you have had priapism is a good sign. To me it indicates that there is probably some lower dose that will still work but that won't cause priapism. I think you are very wise to start with a dose that should be too low, and increase in stages from there.
You may find that constriction before you inject helps with injection reliability. My injection adventures are too explicit for this forum so I have posted more here: http://prostatecancerinfolink.ning.com/group/edandincontinenceposttreatment/forum/topic/show?id=2034917%3ATopic%3A15752