Just curious what the format is specifically for changing the recipes for the flint crafting table (if possible). Just
"type": "flint_crafting_table",
or some such?

almost, you can re-use already defined recipes in this mod (or create new one), e.g.:

{ "type": "stone_age:flint_workbench", "pattern": [ "G G", "G G", "GGG" ], "key": { "G": { "item": "minecraft:brick" } }, "result": { "item": "stone_age:aqueduct" } }