Let me start by saying yes I think you are making the right decision, George had his tail amputated coming up on 4 weeks ago now and he is a different dog after it so much happier in himself it was the right thing to do the infections just weren't clearing up. George is a year old tomorrow and has had 2 anaesthetic in his short life and no complications thank goodness and my vet was upfront and honest enough to say that he was nervous about putting him under and his recovery. Everything went great and I'm sure you will have a similar outcome. The couple of days after he slept 90% of the time, then he came around quite well but after he had the stitches out a week later he seemed to go into a depression wouldn't come out of his crate except to eat and go to the bathroom. So be forewarned it could happen but it will pass. To be sure the vet did a blood test and everything was fine so I put it down to a withdrawal from the many rounds of antibiotics and painkillers he had been on for so long between one thing and another (his little problems are just to many to mention) over the last few months.
George had some very aggressive tendencies before the operation but he has improved ( he still gets mad just not as often and not for as long) so this may well help with that for you also but we too are attending some formal training classes with George and that is helping too. I find most of the aggression here is related to him being tired and when he had the infections of course he was more irritable, he seems better able to calm himself these days since the tail is gone. George does have a problem with visitors in our house though and that is still an issue his greatest problem is with weak men he can't abide weak energy. Sorry I have gone off on a tangent there.
The recovery time I guess differs from dog to dog but it was a full 3 weeks for us but you might be luckier. I understand how sick you feel about it and no one can talk you out of how you feel but it's something that can't be left as it has to be so uncomfortable for them to try and deal with. I was so stressed I got patches of alopicia on my scalp so believe me I understand how you are feeling.
I would like to wish Otis and you all the very best and you will be in my thoughts and prayers please let us know how it all goes. Good Luck