I think it's not the hatching that makes the buildings stand up, but the dropshadow. But they're still really the wonkiest bldgs I've ever seen. Carpenters on shrooms!
Cheers for trying so successfully to mimic that style (maybe yours is too clean, needs some noise/grunge for ageing) ... but I gotta say I don't particularly like that old style. I think your map deserves that you deviate from that style to improve the visual quality of the buildings. Durned if I can find a sample of the ones I think I remember from that period ... European city obliques, approx Napoleonic era or before ... pink and orange roofs ...
Erk ... I knew this Rumsey site looked familiar! ... heh.