Thanks for the further details. I appreciate it.
One thing bothers me:
The statement that says "Made from waterproof and durable tarpaulin PVC".
That is a description that does not tell me much. Most descriptions of dry bags say something like "24 oz. PVC-coated-polyester" or "40 oz. PVC-coated nylon".
This makes me ask the obvious question: Are these bags made of PVC-coated heavy FABRIC, or is there no fabric or only very thin fabric within the PVC on some parts of the bags, making them simply a very heavy PLASTIC, like a swimming pool liner? Simply being heavy does not make them good if most of the weight is from the PVC rather than from fabric.
If they are made from regular dry-bag fabric, then it sounds like they may be a good value, and I'll probably buy them.
Everything is temporary.