What's the best way to deploy a VB business logic with Excel?

[Mauricio Villada]

Let me describe the template file from which many copies will be created:
- Excel 2000 workbook with
- some macros that in turn delegate most of the business operations to a
- COM DLL (built using VB6)

At any given time, multiple copies from this same template could be runnning
on the same PC.

How should I deploy this business logic: as a DLL (I currently do this)?
- turn the VB6 code into macros?
- create an COM Add-in? (if so, how do I do it as I don't have the Office
Developer CD)
- other alternatives

Also consider that it is possible that In the future I'll have to deal with
versioning issues like, templatev11.xls using dllv1.dll running on the same
computer as templatev12.xls using dllv2.dll. In other words, how do I
achieve side-by-side execution

I'm deploying this COM as a .CAB (Internet Setup package) downloaded using
IE6.

Thanks,
MV