Could you please reconsider this decision? Subdomain gateways are fantastic, and great for hosting or sharing websites. However they require a DNS lookup for each different CID which has some major disadvantages.
- The DNS lookup (and SNI) will leak which CIDs you are accessing. This can be a serious privacy issue.
- The DNS lookup slows down the connection time.
For these reasons it makes sense to have both of the gateways available. The subdomain should be used for HTML pages while the single-domain one is better for just about everything else as it will have better privacy and performance.