I also use the trimix. I've done it somewhere around 130x now. I keep a chart listing batch, date, time, location of injection (I inject at 9,10,11, 1,2,3 o'clock and 2 or 3 fingers from the base), maximum hardness, length of erection to half life (half as hard as maximum) and satisfaction. Moving around and alternating sides lowers risk of scarring.) I hate needles but I've persevered. The chart helps me to adjust dosage. This means I can keep the half life 30-90 minutes, with 45-75 being the desired range. If I'm still hard at 90 minutes I take two sudafed (psuedoephedrine) and two more in another 30 minutes, also if needed. This eliminates the danger of priaprism and I keep the med on hand for this purpose. I've only needed that a few times, mainly at the beginning before I titrated the dose down from the initial MD guideline. (While cleanliness is important with any injected med, it keeps well in the refrigerator, but does gradually deteriorate about 20% in effectiveness over 6 months. The pharmacy says they can only "guarantee" cleanliness for one month, but at about $100 a vial, I enjoy spending < $20 a month rather than >$100.) I also located a local compounding pharmacy instead of using the mailorder pharmacy. They only compound it when I arrive to pick it up and provide a packet of ice for the ride home, and it's even slightly cheaper.
Regarding the injector, I haven't tried it. After 20-30 doses I was freaking myself out with the needle, even though I use a RestoreX device to hold the penis for injection. My primary care MD recommended two things: shake while injecting (it is a distraction and also variable insertion pressure) and practice on hot dogs. I never got around to practicing on the hot dogs. 100 doses later I'm doing okay, and the biggest problem with injections is that people get frustrated and quit.
Surgeons market penile implants, so most of the online "seminars" on injections are half seminar and half marketing. (The penile implants have an effective life of about 10 years and have their own side effect and complications profile.) I wish sildenafil or taladafil worked for me, and I still try them about once every six months to see. So far I don't tolerate it well and it doesn't work anyway. If you want links to videos I can look up a couple that might be helpful. There are also a couple books.