Hi Centrino,
Actually, there is a method to set the default App-V runtime drive letter in AdminStudio to support the scenario where you want to use something other than Q: drive. If you are using Automated Application Converter (AAC) to do your App-V conversions, then you can specify the runtime drive letter in Tools - Options - Runtime Drive. Alternatively, you can specify a global value for this in the settings.xml file. This file is located in two places:
Repackager\Support\0409 folder
InstallShield\2012\Support\0409
Towards the bottom of settings.xml you will see the following XML section: /Virtualization/Properties. You need to add an XML element with name Property. It should contain an attribute with the name 'Name' and value 'AppVRuntimeDrive' and also another attribute called 'Value' with a value of 'B:' to use the B: drive as the new default runtime drive letter.
Example:
Make this change in both copies of settings.xml, and then the next conversion to an App-V package using AAC, Repackager, or InstallShield Editor will use the new default runtime drive letter.
I also wanted to address your second point regarding custom actions. AdminStudio can convert MSI packages to App-V packages directly or by repackaging the MSI and then converting it. A direct conversion is fast and does not require installing the MSI package. However, it is not always possible to determine what certain types of custom actions will do during an actual installation by directly analyzing the MSI package. The second option is to repackage and convert the MSI. This can be done with Repackager or AAC. The advantage of using AAC is that it can spin up virtual machines to do the repackaging and conversion in an automated manner.
I hope this helps!
Regards,
Ajay