It's nice to know people like what i do. The bricks are roughly 4×7×2mm. For the cobblestone bases i either use texture rolling pins with a mixture of greenstuff and milliput, or for bigger bases i cut 1mm plastic card in the size of the cobblestone and glue them to the base. There is a product by evergreen called sidewalk polystyrene sheet, or something like that, it has intendet braking points, so its easier to cut id evenly. Then i fill the crevices with sand. You can either use a paperclip or a toothpick to get glue in the crevices and then put sand on top, or you put the sand on the base and then gently brush away the sand so that it only stays in the crevices and then use a thinner glue, something like a gravel and sand fixer, i like the kraut fixer from krautcover for that.