I’ve been adding ground flaxseed to my bread loaves for a few years now; I usually add 1 ounce (~28 grams) to 23 ounces (652 grams) total flour, from which I make 2 small pan loaves. I use fresh ground whole grain flour, usually a 50:50 mix of turkey red and kamut or spelt. I also add other ingredients, such as toasted seeds (sunflower, chia, flaxseed, sesame), pre-soaked rye or wheat whole grains, or dried fruit and nuts (eg, raisins and chopped walnuts), depending upon how I feel.
I’ve never done such a beautiful score; I just cut lengthwise down my little loaves after they’ve risen in my pans. I use a hydration of about 88-90%, following Josey Baker’s suggestion of Whole, Wild, Wet, Slow, and Bold: Whole grain flour; Sourdough starter; High hydration; Long ferments; and Long baking times. Especially the latter, if I ignore my timer for too long.
We eat the bread as open face sandwiches, or toasted. Nothing fancy. But totally delicious!