you might want to check indeed that your SBFS is 40MB (look in the client log, or the file c:\safeboot.fs). But the per-user space will change depending on things like the number of local recovery questions etc.
A Bigger SBFS is ok, it just takes longer to generate. 100MB should be enough for you though.
remember with 1700 users per machine, there will be a lot of network traffic when they start changing their passwords - each change has to be sent to every other machine...
And all known password issues when users use multiple encrypted PC's...Never mind SSO...
You mention the size depends on the number of local recovery questions, now this may seem like a dumb question.... .....but does size increase again if the users have populated the questions with answers, or, is it the case that once you turn the local recovery on then there is no further hit on the SBFS free space ?
Reason I'm asking is I have an upgrade to 5.2.3 in test & I want to use local recovery, but my SBFS is 20mb on my existing clients. Whilst I've been able to see a decrease in the SBFS free space after I've turned the local recovery on, what I cant tell is what, if any, additional decrease I'm going to see when users start to answer the questions.