Hi, I could start as soon as needed.
About the guaranties:
- I can share with you access to the backup server, where you can download/sync the code+ddbb to reply the service elsewhere if needed.
- About the trusted access: I can give access to the /var/www/…/our_service folder (I use Debian servers, and Ispconfig for the hosting stuff), but not access to the server root, because it’s a shared instance (with some other of my projects). We could have an instance just for this service, but then the hosting and maintenance is higher. In this case, I have no problems to share the access and even the « work » with anyone else interested
About costs, I can use a 15DU/hour rate (it’s my standard rate, 15€/h for « nice »/social projects, when not working pro bono). So I think once the service is running, it requires just a few hours to maintenance for security updates, migrations when needed, etc. If there is a peak of work, I can earn the DU using 2 months, etc. but I think it will cost less than 1.200DU/yearly (that will be about 90h!!). But, you know, what about incidences, new requirements, etc? No idea by now 
But in my experience, stable running serves requires little maintenance time yearly (5, 10, 20h?). Anyway, I’m not offering this to you to « earn money », just to « practice » the june economy
Ps.: I forget hosting costs: for a shared server, 6DU/month could be fine (depending of space required): https://calbasi.net/hostatjament_basic (1Gb)
I just need to know the repo URL and your repo should accept my ssh public key (I’ve tested it on Borgbase, and it was very easy).