[Zope] load testing for zope server..

Dear firends, Greetings! Has any body done load testing for zope on different os/ platforms. are there any tools avaiable to do the same. For a project of mine, I need to run zope 2.4.3 on win nt 4.0 sp 6 with P3-600 MHz and 128mb ram. The zope server may have 1-2 users authoring the site all the time. I ma start with 1500 object and 3 months down the line it may reach 1,00,000 objects. How many users will be able to simultaniously browse the site?. How do we calculate the max load that the zope server can take? Any sharing real life statistics will be of immence help. Regards, - sree