Thanks for the reply shonk.
I believe you are correct, REQUEST_URI is not supported so instead I used PATH_INFO and match it to (/blog/.) which seems to match fine. The rule however still does not work. It actually renders the main site inaccessible.
So here's what I think, three base rules are in order:
1. redirect non www to www (regardless if blog or not)
2. if url is not blog redirect to https
3. if url is blog redirect http
THEN - All other blog related rewrites
Any help on creating those three rules would be appreciated :)
And regarding the $1, Im certainly no expert so it probably is a general rule that can(should) be made more descriptive. Any suggestions will be welcome.