Something like that. Any mechanism that prevents the tank filling up in a manner that would make it better to just feed more than it would have an external reservoir. I'm not saying that's the case. I'm saying it's an additional practical concern regarding the feasibility of making a gas can.
Sure, but not by me. A thought occurs to me that the difference between one wamp and another might be about fuel efficiency instead of the tank's capacity. Both is more likely than either/or.
I think it works either way.
We know that the "Hunger" of Wamps is variable, and how Lord Raith established dominance. I don't think we know the exact nature of that, because we're used to thinking of hunger as a state rather than a force.
Maybe the "Hunger" is equivalent to allure, and his ability to overwhelm the senses of others is his only advantage. Maybe there's no top to the tank, and it can be infinite storage for any wamp.
But clearly it doesn't work that way, seeing how often Wamps run out. Thomas has been drained numerous times, Lara's sisters needed immediate feeding after the battle with the Naagloshi, and Lara was spent after feeding Thomas.
Wamps just don't seem to have the ability to sustain their power without constant feeding. Except for Lord Raith, who managed it for almost thirty years.
So I'd still argue that them having a snack pack in reserve would be valuable.
It's basic banking. You can keep all your money in your debit account, but if you do that, you might find yourself overdrafting due to poor budgeting and an untimely expense.
Putting some money into savings as you go might mean a little less to spend along the way, but over time you get used to the budget, and then if something happens, you've got a reserve to draw from.