With Moon he is on free choice hay 24/7/365 because my pasture is essentially a big dry lot. He also gets a few lbs of safe&Sound each day and 1 cup of plain cleaned oats in the PM. If he is in a state of gain I cut the feed according to his needs at the time.
If you can, stay away from molasses feeds. They really have too much sugar for most 'normal' horses but draft horses too. Drafts do best on a high fat low carb diet. Safe & Sound has no molasses and is a bit higher than fat then some regular feeds around here so I've found it to work perfectly for it and I haven't met a horse who turns their nose to it.
Most drafts have slow metabolisms and giving them as much time to move around works for them best. Keep them cooped up in a stall too much and at times you are asking for digestive problems as well as stocking up in the legs.
also as a heads up, the thicker bodies and thicker muscle mass makes it hard for them to cool off in hot weather. Moon stands in the shade this time of year and is covered head to toe in sweat or dry white crusty salt from sweating so much. There have been days he will literally have a puddle under him. the only time I can work him is early day or late evening.