A little side question from me, would it be possible to have a catapult set up so that it shoots the stone down a corridor, and makes the stone land in a stone stockpile next to my masons?
Stone must fall, after a catapult flight, to be useful at the end. (More or less.) If you dig a channel in front of the wall that (most of) the stone hits, then in that channel you'll end up finding any such 'launched' stone as you have. Similar solutions with raised drawbridges in the way, instead of a wall, also work as long as you have the same drop.
Whether you could designate the drop-zone as a stone-pile (make it accessible via stairs/ramps, if you want your stone-using workshops on the 'launch' level) or it would always want to be moved 1:1 with stockpile space and you might as well let them drag it a short distance to the 'existing stockpiles is something you might want to try out.
Personally, I build masonry buildings in the midst of a 'stone farm', and churn out blocks/items of the desired material from there (it's a pain that you can't use the vanilla job manager to say "a throne of RHYOLITE, please!", or "I need thirty Chalk blocks, and could you please mark them as reserved those for building purposes?"... I know there are tools that will let you do this, though), then have to working out the subsequent hauling logistics accordingly (oh yeah "blocks, rock, alunite" would also be a useful extension on the stockpiles customisation, though I'd be surprised if it hadn't been suggested already).