Territorial Claim Unit (TCU) - used for actually claiming sov = 5000 m3
Sovereignty Blockade Unit (SBU) - used to attack someone else's sov = 2500 m3
So the act of claiming or attacking a system requires some minor hauling ability, but nothing that Blockade Runners even could handle. Now, what about the upgrade structures.
Infrastructure Hub - the structure upgrades are attached to = 750,000 m3
Entrapment Array 1 - the lowest level upgrade to add permament complexes to a system = 5000 m3
Entrapment Array 2 = 10,000 m3
Entrapment Array 3 = 100,000 m3
Entrapment Array 4 = 250,000 m3
Entrapment Array 5 = the highest level upgrade which adds a whack load of permament complexes to a system = 750,000 m3
The other military and industrial upgrades appear to follow the same size progression as the Entrapment Array. And the Strategic Upgrades?
Advanced Logistics Network - allows the anchoring of jump bridges = 400,000 m3
Cynosural Navigation - allows the anchoring of cyno beacon generators = 400,000 m3
Cynosural Suppression - allows the anchoring of cyno jammers = 500,000 m3
Supercapital Construction Facilities - allows the anchoring of Capital Ship Assembly and Maintenance arrays = 200,000 m3
With the old sov system, getting a number of POS and their fuel supplies into position required a fleet of industrials and jump capable ships like Jump Freighters and Carriers and Rorquals. The new sov system in Dominion doesn't require POS fuel but the sheer size of upgrades will mean that alliances will need a lot of freighter pilots and convoys through dangerous low sec and null sec space will become more common, especially during times of sov expansion like right now as the switch over is in progress.
And people will be on the lookout to take advantage of this new reality:
NULL SECURITY SPACE - Multiple freighter fleets suffered severe losses this evening as massive logistical operations took place all across New Eden. The latest reports indicate twenty-seven freighters belonging to RAZOR Alliance [-RZR-] and SOLAR FLEET [SOLAR] fell victim to hot drops in separate attacks.Twenty seven freighters down, ten in one fight out of a fleet of 25 and 17 in another fight. A lot of infrastructure hubs found in the wreckage. If you have a researched freighter BPO, I'd be building them like mad at the moment. And ops to escort freighters are probably going to become a more common occurrence in New Eden.