1000 sheets of printer paper is 10 pounds. Seals are a bit smaller than this IIRC but they are also made of a less refined version of paper, and they have paint all over them. A gallon of paint covers about 400 square feet, so I'm going to roughly estimate 1000 seals will take a gallon of paint. That's an additional 7 or 8 pounds. 17 pounds per 1000 seals is over 400 pounds, plus the weight of whatever container needs to carry several hundred pounds of stacked paper. On top of that, 25000 seals is way too few anyways as we mentioned. I said I'd expect it to take hundreds of thousands of seals, where the weight gets truly ridiculous and by no means is solved through reverse summoning if we're talking about enemies being nearby.
We still don't even know how much weight we can reverse summon at once, too.