Article 1 section reads in part:
To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the Acceptance of Congress, become the Seat of the Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings
I agree that the feds own too much land. However to correct the situation, we will need a Constitutional amendment as this is an enumerated power of Congress. I’d like to see the feds limited to 20% of a state’s land mass.
I'd be inclined to start right there. We need to at least start by enforcing the Constitution as written without having to repeat the requirement with an amendment. The feds need to prove what is "needful" in the lands they own. Much of it is obviously not "needful" to the feds, all those badlands and deserts in the west. It's koo-koo. So moves should be made by the states to rescind their consent for those lands the feds don't "need" and force a buy-back at a fair and reasonable price.
Failing that, then yes, add land mass to the CoC proposed by the Citizens for Self Governance.
I seriously doubt that the gents who wrote the Constitution, creating a “Federal” government to do things better done “collectively” rather than by the states individually, intended for their creation to control the majority of land west of the continental divide.
I do not acknowledge any interpretation that suggests they did.
As you’ve been told, 85% of a State exceeds the “fort/dockyard/post office” limit in Art 1 Sec 8 sub 7/17.