My advice would also be to change hosting provider to one which does have Let's Encrypt integration and has it enabled automatically for every client for free.
If that is not an option, you might want to consider using CertSage (CertSage ACME client (version 1.3.0) - easy webpage interface, optimized for cPanel, no commands to type, root not required). It's mainly developed for the GoDaddy hosting provider, but there's a good chance it also works with TSO Host I think.