NT speeds-ups?

We have a client running on NT and an Online 7.2 server running on UNIX over a slow WAN. We need to squeeze every bit of performance we can out of the communications link. We are doing the obvious things to ensure the database runs fast and trying to move some processing into stored procedures. Replication is not an option due to support and maintenance cost and purchase expense of additional equipment, and culture of centralized data management. Therefore, has anyone got any tips about: 1) Reducing the latency in the client/server connection. 2) Packing more bits into the same space on the line? Things we have thought of: 1) Larger TCP/IP buffers on NT. -- Can this be done? how? 2) Using more compact datatypes. 3) Ensuring we are doing select col1...coln and not select *. Any other ideas? and successful results that can be shared?