If I was going to have a Sustaniac I would just do it myself and figure it out as I go along, but if I needed it done there are tonnes of people within reasonable driving distance who could easily do the job. If you live in a populated area you can surely find plenty of people capable and willing to do it, especially now during the pandemic when work is harder to come by. Having the sustaniac people themselves install it wouldn't even be an option for me living in Wales, I'm surprised that's something they do to begin with to be honest.
If people know where you live they could recommend techs. When I snapped the neck on my 7V I came here to Jemsite for luthier recommendations, someone recommended Rob Williams (Rob Williams Guitars, UK) and that's who I used, he did an amazing job.
I like my privacy.
maybe you underestimate how difficult that installation can be. I was told by Maniac Music that they always get calls and emails from techs and people who have no clue and have trouble doing this installation. Yes, they do the installation, but apparently, not as much anymore. I was told they would do some limited installs in the summer, that's like 4-6 months from now. They don't want to put me on a waiting list or accept a deposit, so basically, if I sleep or forget about it, I lose my chance. It shouldn't be like that.
Unless these forum people live in the same area that I do, their recommendation would be based purely off an internet search, which I have already done so countless times before. I'm very good with the internet and researching stuff. I have googled, yelped, Angie's list, and many other websites. That's how I found the techs I went to.
I chose those techs cause they have the best reviews and decades of experience in guitar tech, yet they couldn't set the angle and action of my guitar correctly. I had to do it myself after reading and being taught by some fellas here. I basically wasted my money on them.
This is my one and only guitar, I don't want to trust some random tech to do this installation and possibly mess something up.
I'm not in a hurry to do it so I'll just wait.