Hi Wendy
It seems that nobody has sent you a reply.
The Blaise software does not enable you to know how many users you have. That is something that you can do using other 3rd party software which can monitor (and control) the usage of particular EXE files in a designated folder. The trouble is that such a monitor is much harder to set up if each user has their own installation of Blaise.
Users who only need DEP and the Manipula executable do not need to have a licence key. A licence key is needed for anyone who is likely to compile (ie. prepare) a program.
The situation gets a little complicated if you are using the API. We have found that if the Blaise.EXE file is present with the API sometimes (or maybe always) the system needs to have a licence key. The solution in that case is better to remove the Blaise.EXE from those person's installations rather than insert the licence key (which would be more expensive).
When it comes to licence negotiations you need to be able to estimate (and substantiate) the number of concurrent users of each type (ie. developer or user) are likely to be using the software. It is in your interest to keep the number of developer installations down.
Depending on your installation access restrictions at the PC level it may be possible to email the saved registry key (as a file attachment) for a valid licence to all those developers who need it. If your site has significant restrictions on installation of software (as most larger organisations do) then you will need to commission the creation of an installation script for the new licence key which can be invoked by selected operators that have administrator access to your PCs.
Good luck
Fred 