Load and Concurrency Testing

I work for a small company that has a VB/SQL 7 application. We do not have the resources ($ or people) to do sophisticated load and concurrency testing, but need to know if the app will scale to 100 concurrent users without errors or performance problems. I have built a utility that does random updates to a database to 'simulate' user activity, but am not sure how helpfull it really is in addressing this problem.

The utility randomly picks a table, and updates a random row in that table using ADO to set a field to its current value. It has options to use optimistic or pessimistic locking, and another option to specify how long to hold the lock before committing the update if pessimistic is on. Updates occur on a timer event (I used the CCRP Timer dll) that can be configured to fire on any millisecond interval.

I hope this will help simulated a greater load on the database. Any feedback on the usefullness of this tool, caveats, or freqeuncy and lock duration settings would be greatly appreciated.