That's exactly what I do... I use B-D 31g 5/16" 0.5cc insulin pins for everything, they're the sharpest and best. TNE w/o solvents, DHB, and Primo go on the warmer every time for a couple min. Used to do mostly subQ injections but finally got lean enough where I switched all oils to IM. I alternate biceps, triceps, pecs, delts, hip flexors, and quads. Still have a bit of fat on my ass and love handles so do water-based injections there subQ (L-carnitine, GH, Reta, IGF1-LR3, Selank/Semax, BPC157/TB500, Cu-GHK, etc). High volume water based IM injections like L-carnitine carry higher risk of infection, so I try to avoid them. Risk of infection with subQ is essentially zero.
On another note, I added a little DHB (15mg/day) and EQ (30mg/day) at beginning of Sept when I d/c'd primo (30mg/day), and my strengh has already significantly increased after being at a plateau for a while... DHB might be the best compound ever for strength. Zero PIP with daily injections and no side effects yet. DHB is from DutchPharma USA if any one is interested, great domestic source on ASF.
The EQ is from OEP Labs here. I know it takes weeks to build up, but I haven't had to dose aromasin since starting it, so unlike primo EQ might actually have an fairly strong AI effect in me. As the EQ builds up I'll slowly increase my trestolone dose. I keep test low as I don't want excessive DHT for hair/prostate.
For older guys like me concerned about hair and prostate health, EQ + trestolone with very low dose test might be the perfect combo.