Thanks Mika. Sounds a bit complicated, but I think I get it.
As a follow-up question:
Would you recommend me to keep the subdomain structure, but on multisite? Or would you change it into a sub-directory structure? If the later, than what’s the best way for doing so?
Basically, the main and only reason why I have different installs now is to be able to have two sets of permalink structures (with date showing on the blog, with no date in main site urls).
Thank you!