Is IWP appropriate

I have a potential client, who wishes to use IWP to publish a database that allows agency staff to log in and record the months, days in the month, and times and other criteria about which days and times they are available to work.

Parallel to this there is another module that provides for the institutions who require staff to fill particular rosters, to login and record what sites/days/ times/shifts etc and level of staff they require.

The client then matches up the available staff to the institutional requirements, in order to fill rosters.

I have always been under the impression that IWP was not an appropriate implementation for this kind of situation, and that a CWP was effectively mandatory; planning and developing a FMStudio or Lasso generated implementation.

The current active staff level is c600, though this may grow to 2000-3000. Only a minority of these (the 600) would be expected to access concurrently, and not all would wish to use the web service at all, preferring to phone in their details. So concurrency may not be a limitation.

The implementation does require absolute security though.

I have always been under the impression that although IWP was more appropriate for LAN situations, and whilst WAN capable, IWP was not really appropriate for 'serious' WAN applications.

Recognizing that there are some browser version limitation in IWP, and I have yet to locate and digest information on the status of IWP in FM10 (potential client has FFMS10A), is IWP a practical way to go for such an application?