The minimum is 1/8″, or certainly more. BUT, for a kitchen countertop, I believe you want the tiles to be as tight to each other as possible. Sorry, I don’t have a photo. Perhaps you can visit a Kitchen & Bath Showroom, or visit a bookstore for pictures. Heck, for the $$$ you’re saving, why not spend a few of those saved $$$ for ‘expert advice’ in a book? In this case, I’d consider it $$$ well spent.
My best to ya and hope this helps.
Jay J -Moderator