I use a 12 x 17 baking sheet for all my sheet pan recipes. This accommodates a lot of food without overcrowding. If your baking sheet is smaller, use two instead of one. (Don't overcrowd.)
If you don't have baby dutch yellow potatoes you can use regular yellow or gold potatoes. Just make sure you're cutting them down to the appropriate size. If they're too large or too small they'll be under done or over done.