If budget will allow, always buy the largest capacity baker that you can, the difference in price, footprint and running costs is very little between the two sizes and you can always utilise any unused oven capacity for something else.
Get your first batch of potatoes in and cooking in plenty of time. If you need to serve from 11.30am for example, have the first batch cooked and in the display oven for 10.45am. Put the second batch in to bake and by the time the display oven is empty the next batch will be ready. Once baked and on display, we recommend that you serve the potatoes within 1.5 hours of cooking. Any potatoes not used can be refrigerated, sliced and sprinkled with oil and paprika and baked for 10mins to make tasty wedges or you can use the flesh to thicken soups or stews.