I worked from a recipe and advice I found here. I used a small handful of instant mashed potatoes that I cooked in about a cup of water, with a tablespoon of nonfat dried milk.  My goal was to produce a loaf that was more like "normal" sandwich bread for my husband. I used the directions for 66% hydration, and counted the mashed potato-milk-water mixture as almost 100% liquid (added enough water to make 330 grams liquid to 500 grams KA unbleached all-purpose flour).

I used a beaten-egg wash. I found it made the "heel" a bit leathery and too eggy-tasting for me personally, but the slices were fine-no eggy taste. Slices toasted nicely.