Delta Green as a basis of "Base Earth"

My first decision is whether to go with the base description of Earth from the core book -- or to modify it.  I have decided to modify it in various ways to allow me to tell stories in the dark conspiracy genre I would like to play with.  Specifically, I want to emphasize these specific aspects of my Strange Earth

• No exactly real physics -- a little magic and a little sci-fi tech
• Government and super-government conspiracies
• The necessity of players to cover for their actions -- not just running around guns blazing
• But, not spending all of the time talking about cover identities
• And, most importantly, a setting which allows me to have elements from other recursion

Physics:  

I will probably write on this more at a different time but I have some misgivings about how the core book treats Earth physics.  The game refers to Earth as "standard physics" but then includes a lot of pretty high tech elements that border on weird science.  The launch scenario "Eschatology Code" has weird tech operated by enemy agents, for example.  I like their weird element and I will embrace it in my core Earth -- but I recognize this contradicts a by-the-book interpretation of "standard physics."  My flexibility with physics will let me be looser with invasions from other recursions, etc.

Conspiracy elements:  

The core setting includes some fodder for conspiracy stories.  Most notably, the OSR (Office of Strategic Recursion) provides some opportunity to look at government conspiracies from the inside (with players as OSR members) or the outside (with OSR agents as antagonists).  I am borrowing from Delta Green because I want to take this even further and link it more specifically to existing government organizations.  The history of Delta Green leans heavily on he actual history of espionage -- which I anticipate will provide nice background for my stories.

Cover identities: 

 This is something I am still struggling with.  The core Strange setting seems to allow Estate operatives to pretend to have an official sanction a little too easily.  I can see the reasoning here.  Having players constantly having to create cover identities, start most encounters with a deception check, etc. could get tedious.  As it stands, GMs could pretty much hand wave the need for credentials to get access to locations, carry heavy weapons, etc.  When they want to create an encounter where the credentials are questions, it still fits within the framework of an Estate campaign.  My background in government administration (especially homeland security) makes want to ground it a little more in actual credentialing, etc.  This is why I am leaning towards a Delta Green approach where players are members of actual federal agencies with understood credentials and limits ("Why is an EPA official carrying a machine gun?").  I am curious to hear how other people react to the question of credentials for Estate operatives in the core game.

What do you think?  I would love to see more discussion of how people are handling their own Strange campaigns.  

In the future I will add stats and reskins for my Delta Green inspired version of the core Earth setting for The Strange.