Should I use a page from one site to create another in a multisite?

I’m building a multisite network with the main site under the store brand name. I have sites on domains for each product brand we carry. Should I build the product page on the main site and use the multisite copy tool to create the home page on the product site? or build it individually? Beside the database usage, I think the only difference is how search engines read and rate the sites, which I don’ t know yet.