((((jesmar)))) I am so sorry for your loss. I remember your earlier post and it is so sad to hear that at the ER your kitty got worse, sometimes that is just what happens with DKA. When you stopped the insulin, your cat continued to act well and get good #s, so how would you know a problem was about to surface? Other people have taken their cats off insulin for one reason or another, or delayed starting insulin after a diagnosis, or have had cats unregulated for long periods of time (myself included!), and were just lucky I guess that their cats did not get DKA.
I understand your wanting to get an expert take on it, but you (and I, and lots of vets even!) are not an expert in feline diabetes, so even if things could have been done differently, how would you have known that without being an expert yourself? My experience with my own cats who have died is that in hindsight sometimes there are things I would do differently, but at the time I always did what felt right in my heart to do. If I was wrong, well, I guess I'm human. Please don't torture yourself with "what ifs" (I know that is easier said than done). Sometimes things just happen the way they happen, and it s*cks.
You may also want to post over on the Grief forum, there may be additional support there that you might find helpful.
Fly free sweet little one... wings_cat