I thought the rule of 1:2 ratio for agent:port continues up to 400:800 and I couldn't find a formal document describing it's limitations except your answer in below discussion that total ports would not be more than 400 even premium seats exceed 200
and what is eventually going on, is that 3 stanalone UCCX servers are working in line to handle 1200 calls at the time being. :)
thank you so much for your helpful reply Anthony.
by the way, I am going to purchase a ucce course, regarding your helpful comments I'd like to ask you which would be better for a capacity of maximum 2K IVR ports, UCCE or Packaged UCCE?