Merging a 3.6.4 and 3.8.0 system to 3.8.4
 

I have had a developer doing this to date as a trial run and I think i can do this myself with his help if necessary.

The first trial run did not go perfect.

The goal is to merge a VB3.6.4 site and a VB 3.8.0 site to a common 3.8.4 site and then later to a vb 4 site.

I would like to do a new trial run and here are the steps and questions I have.

3.6.4 system is #A
3.8.0 system is #B
3.8.4 destination system is #C

--Importing system #A to system #C

* Make clean install of 3.8.4 on systemm #C
* Install Impex with VB 3.6 support
* Reference DB dump from system A that has attachments in DB
* Import with Impex
* Inspect and clean up.

--Mergeing System #B into system #C

Note: this is where I am unsure of the steps.

* Make DB dump with image attachments included of system #B
* Import with Impex

Questions:

1) What impex/system/ folder and files do I use for this? There is a Vb_36 folder but nothing for Vb_38.
2) Do I simply reference the filename of the dump from system #B in the ImpexConfig.php file at $impexconfig['source']['database']
3) Should I do a separate upgrade first of system #B 3.8.0 > 3.8.4?
4) Should I make the merge at 3.8.0 and them upgrade all to 3.8.4?

Thanks