SharePoint Global Templates Gallery Location

I have a group of users that periodically updates the template for their project sites.  Each time they make an update to the template, I upload it to our Global Templates so I can create site collections from this template.  However, to do so, I must delete the prior template.  Each time I do this, it increments the '_GLOBAL_##'.  As you can see from the enumtemplates output below, I only have two templates loaded into my farm.

C:\>stsadm -o enumtemplates
Group1 Project Site - Language: 1033 - Site Template: _GLOBAL_#1 - Template Id: 1
Group2 Project Site - Language: 1033 - Site Template: _GLOBAL_#6 - Template Id: 1
     Default project site containing all the necessary lists and libraries

C:\>

1. How do I just overwrite the existing template?
2. If I can't just overwrite, how do I keep the template global ID from increasing?

If I delete a template that WAS _GLOBAL_#2 and then upload a new template, I want it to also be _GLOBAL_#2.

The reason I ask is because my secondary script creates the project sites programatically (using stsadm -o createsite) but has to be updated with the site template ID change each time...