Not recommended as you will use much too much material and the coating will crack.
No. Will not working.
It will seal the brick pavee but if you have large spaces between the papers it will not fill in to form a smooth surface. If your papers are seamless it should work.
The trash pump systems typically don't take sand. Air diaphragm pumps are the best way to transfer material.
Using squeegee application with generous coverage I cover a 12 foot wide driveway to a length of about 150 feet consistently. That heavy coverage lasts about 3 years, if you spray it on or squeegee thinner, it lasts 1-2 years at best. 12x150=1800 sq ft.
Barrel has a standard size large and small bung. Much easier just to remove the lid entirely and mix the contents, then replace it. It’s easy
Open top drums.
I do not think it will work the way you are expecting it to. This is an Asphalt Sealer designed to go on stable blacktop to seal the cracks that develop over time in Asphalt . it dries very quickly when we applied it. it was a sunny day and temperatures in the high 80 and I feel the limestone dust will interfere with the adhesion of the sealer. I also do not think it will hold up on the gravel surface as the gravel has too much movement when driven over.