Shopify Bundles

definitely a good starting point in theory, but when in comes to practice...
when I create a bundle of 6 products, my POD partner won't get the information of each 6 SKUs, but only the (self-created) SKU of the bundle, which he can't use in our fully automated process.
AND: if I create a bundle with products of multiple variants, e.g. 3 products with 3 sizes each, my customers are not able to select the size for each product in the bundle. only one product in one size can be selected - and the price doesn't change either...