Great question @chrisdjbell , and the answer is that we can only support up to about 50 names on a single site.
But of course you can deploy multiple copies with a different list of names on each, so effectively we can host any number of hostnames for the same codebase.
This will work best if you provide an SSL certificate, or if we manage your DNS for a domain and all hostnames for a site match the pattern
something.yourdomain.com since we can issue one wildcard SSL certificate to cover all the names.
But up to about 50 random names will work ok too even if we handle the SSL provisioning. SSL provisioning will take QUITE awhile for sites set up with >20 names, and unless we help you with it, you’d be limited to <= 20 hostnames PER WEEK added to any single site (our SSL provider has strict rate limits and adding names one by one will hit them around 20 total names).
Best practice here would probably be to provide your own SSL certificate to start with, to ensure a smooth transition, and then we could help you migrate to a managed one once DNS is all correctly pointing to us.