Philip,

>1. We could pass data from the server to the client in hidden fields in a form, and then resubmit them to the server.
> - Some of the data we keep track of is XML (about 20K per user). This seems like a lot of unnecessary activity over the wire.

>2. We could store data in a DB Table, and pass the record id to the client, and retrieve the record when the next page is called.
> - We are expecting very high volume, and feel the SQL Server may be a bottleneck.

No need to pass the actual data back and forth -- just track a unique ID # that is tied to entries in a table on the server. The ID can be stored in a cookie that you check on each hit, embedded into the URL (called license-plating), or sent as a hidden form variable.

Web Connection comes with a pre-built class, wwSession, that can handle all of the logistics of storing/retreiving to/from the table.