[Taqwus]

Yeah, typo w/ MAX/MIN.

Once you have the construction research for bags, aye, go with the bags unless you have extremely few nature mages but a glut of nature gems (in which case, why aren't you summoning Lamia Queens and -getting- more nature mages) or need the supply ASAP. Slots aren't a huge issue since scouts can carry the bags... and the scouts can also carry gems/slaves for rationing purposes or items you may want to withhold based on the situation (say, Staff of Storms, although Atlantis with its lack of missile/flying troops will rarely have a reason to not like Storms unless meeting an air nation with units getting storm bonuses... and in that situation it's not like the storm isn't going to happen anyway.)

Using more scouts/slots also somewhat reduces the impact of a spell remotely killing one of your scouts.

The sea troll summons might still be interesting for the Sea Kings; what are the requirements for Quickening, for instance? The trolls themselves, hm... perhaps not that impressive. Perhaps clams, then Abominations for something still vaguely thematic (more R'lyeh ish 'tho) after you're done equipping the Elemental Queens of Water. Or Wolven Winter + Murdering Winter...