Shame you've had such a bad experience that you have to opt for the higher expense of hospitalisation. I've been so lucky with my vets, both practices I've used in the last 15 years or so have been superb at standing castrations at home, minimal fuss, no stress for me or the colts, and no hassle from the practices either.
I have only had to send older ones or ones with issues to the Dick Vet for surgery, 2 welshie rescues a few years back that were late descending (1 each just out of reach inside by 18 months) and even had a 7 year old stallion and 2year old colts done at home in the past, tho I pray I never have to go through that with my now 12yo homebred stallion as that would be scary at his age.