Lucky that 415031 is prime :)

The steps described in the article sound familiar to the process done in the early 2000's, but I'm not sure why you'd want to make it hard for yourself now.

I use certbot with "--preferred-challenges dns-01" and "--manual-auth-hook" / "--manual-cleanup-hook" to dynamically create DNS records, rather than needing to modify the webserver config (and the security/access risks that comes with). It just needs putting the cert/key in the right place and reloading the webserver/loadbalancer.