Oh Mama IndigoLori, to answer your questions right away: Yes, you did the right thing, and Yes, your loving Taz will not only "forgive you" but he will ask, what do you need to be forgiven for? You saved him from a fate that you know he would not want; that's exactly what you did.
I am with you, Lori, that our animal children deserve their dignity, and for some, it is one of the strongest personality traits, as it is / was for your Taz. Like you, I have always placed so much importance on their dignity, and I always tried to downplay anything that might happen that would put that at risk. I so respect your decision, and the timing of it. You are suffering terribly and in deep sorrowful pain, but you would not have been able to live with yourself if you had used "extraordinary measures" just to keep Taz with you a few more weeks. The guilt would have not been lessened. :(
If there is anything I have learned here it is that "better too soon, than too late" -- that is the universal truth, even though the decision feels like the world (and your heart) just crashed into a million pieces.
Taz, the doggie baby monitor (love it) got a real winner in heaven, when he exploded though those gates.
Hold on, hold tight, keep the faith, and please accept my sincere condolences for the loss of your handsome, gorgeous, loving forever dog, Taz.
I stand with you today, and hold you and Taz in my heart.