I was really skeptical about site injecting too, but i started doing my biceps both once a week on my last cycle and really liked it actually. They actually became my primary injection points and, well, they’re a lot bigger now than they were pre-cycle, but so is the rest of me i guess. There is a bit of a trick to spotting properly and you’ll hit veins a lot more often (always aspirate!). Make sure you use a brand new pin (not the one you drew up with, it’ll be dulled a bit and believe me it hurts more when its dulled). I was using 23g1" pins with 3cc cases no trouble, just go in slow and listen to what your body is telling you.
And i definetly agree, avoid the calves, they hurt like a bitch, at least in my experience. As for gear, i was using EQ for my spots. I used eq/sust in my bi’s once and i probably wouldnt do it again because i’m fairly sensitive to prop and it hurt to do anything with my arms for a day or two after. Some people recommend prop for spotting though because it causes some localized swelling which transtlates to size, albeit temporary. Others swear that spot injecting makes the muscle way bigger, so i dunno. Personally i think its probably just swelling.
I found spotinjections.com pretty helpful, you might have been there before though.