Wow... How did you muster the courage for this?
You are obviously also not sedating/anesthetizing the birds and I understand that this is usual for castrations done outside the office of a vet - but I admit that I find that part hard to 'overcome' (- which is more an emotional response than an intellectual one).
Did you study the procedure through videos?
And lastly, do you use special lights (headgear?) to see inside the cavity?
On a more general note, do you have any thoughts re: a caponization at 4 months of age on roosters that have started to practise first crows? Any chance this behaviour could eventually subside again?
I am working with a vet willing to perform this procedure but 'we' are still waiting for the right tools to arrive and the clock is ticking...
Oh, and I should maybe also add the other complication - namely that I am dealing with bantams.
It wasn't easy, this is my first year in on trying to caponize birds. During my first caponizing surgery I was so anxious and my adopted grandma made me finish she said "You got this bird opened up, if he dies during the procedure then he dies as a capon or die as a rooster if you chicken out!", he lived by the way. His name is Ozzy, a black copper maran, he's my first ever capon. After that it got easier, some cockerels hardly respond to the procedure and some scream bloody murder before I even apply the alcohol. At the moment, I've caponized 33 cockerels so far and I lost one during caponization, I hit the artery

. I always dread the procedure but once it's over they go back to eating like nothing ever happened. I do feel a sense of accomplishment a couple weeks post operation and starting to see the capon development. I think it's a perfectly understandable response to not want to caponize, so don't be hard on yourself for that.
Headgear light is an absolute necessity! Sorry I forgot to mention that. I study videos meticulously for months and practiced but let me say this, practicing and doing the real thing is not the same, it helped but it wasn't the same. Also every bird is a little bit different on the inside.
I've not caponized a four month old bird yet. I have caponized birds that we're 9 weeks old and beginning to crow and it's been two months since and I've not heard a peep and I'm around these birds from dawn to dusk nearly every day. I was told that caponization is most effective before crowing and that crowing birds may not stop. Sooner is better than later.
I've caponized four bantam birds so far, 1 mix and 3 millie fleur bantam cochin. The issue is with the bantams is their size and the rib splitters broke some of the ribs. They've healed up great and I wait a bit longer on the bantams to give them some more size.
What breed is your cockerel?