My setup has an internet entry router (with a wifi called EXTERNAL - for simplicity) that is connected to a TC (with wifi INTERNAL) in bridge mode. The server is connected via wifi to the TC and has a fixed IP address. All incoming traffic is directed to the servers IP.
If I connect my iMac to the server using INTERNAL the response times are real bad.
If I connect my iMac to the server using EXTERNAL the response times are decent.