I agree with @Backpackingvet , so not really the best idea mate, especially when you can just buy a ring off the shelf, and the price difference.
What sort of searches have you done for installers?
have you approached some body piercers? (better in person than ever the phone)
HOW TO APPROACH AN INSTALLER
You could also try a medical professional that you don’t know, if the ones you do won’t help… but if you don’t ask them, you don’t REALLY know what they will say.
Just make sure you have the knowledge to answer their questions and a valid argument as to why you want it installed.
Worse case, you could guilt trip them 
“I came to you because I thought you were open minded”
or
“I came to you because I am going to do it regardless, but thought it better / safer to have a medical professional like yourself to make sure I don’t stuff it up; here is some installation information you might want to read through (hand them preprinted install guide)”
if you have no luck there, you could also go to a veterinarian, as funny as it sounds, it is totally valid and viable approach.
Same approach technique as a piercer, but just explain how it is EXACTLY LIKE a pet ID chip and show them the needle, they will be very familiar and hopefully comfortable.
You could even offer it to them as a training opportunity, let a trainee vet do it, easier to see and feel what is happening without fur in the way. (legality and stuff may get in the way, maybe put together a pre-signed waiver to present to them (only if they bring it up first))
if all of those fail
Find somebody to assist if you can.
Much easier than on your own.
Get them to Watch the videos, read the materials.
Many people have done self installs successfully, but it really should be your last resort…
These should help
BEGINNERS GUIDE
IMPLANT SUTRA
I hope that helps, let us know if you need more links to references
keep your thread upto date with your journey
good luck
Any more questions, just sing out