75mcg of T3 destroyed me. Was taking 50mcg just fine, 75mcg just fine (for a few days) and then one day I had a super shitty workout and almost looked smaller by the time I was finished.
Dropped down to 50mcg and still couldn't fill out. Tapered down to 25mcg and was still flat, but then I filled out after about a week. Might have just been some strong ass T3, but I tried it again and around 50mcg is where I hit the ceiling.
Getting more on topic, if I were to run insulin I'd take 25mcg of T3 and coast on that for a bit. Take whatever anabolics to keep protein synthesis cranked, get good sleeps and just train and eat smart. I don't think shorter bouts of insulin are that detrimental. I think it comes from the off season neglect. Just bulking up like that with no slin is very unhealthy for the heart and for the physique. I think slow and steady is the only safe way. You can throw caution to the wind, but it's your body and you should take it seriously. You have a great physique so don't let drugs like insulin ruin your solid work ethic. You didn't build that foundation from cutting corners or slacking, that's for sure. A little slin can be a great tool in your arsenal.
My experience is mainly limited to playing around with it and using a blood sugar monitor. I tried pre and post workout doses at higher levels but I wasn't taking enough anabolics or using insulin aggressively enough to see massive gains. I can however see how potent of a hormone this is. I used humalog, and if you use it, watch for the second peak. It doesn't just dump you sugar once, it can come back with a vengeance. Also, don't panic. Diabetics take a couple 5g glucose tabs and wait it out. So if you feel hypo, just take in some carbs, sit down, let your adrenals go crazy for a bit and settle down. Best to tell the wifey or GF if you're taking a high dose too, just to keep an eye out. I took beta blockers and went into a severe hypoglycemic attack and almost fainted because the beta blockers masked the symptoms of hypoglycemia. It's weird shit like that you never expect.