A flour corn (Painted Mountain), winter squash and pole beans intended for dry worked best for me. And, I put some poles in that part of the garden to assist the corn in holding up the beans. A "rattlesnake" bean was used. They are usually eaten fresh but make delicious soup after drying.
I tried the Sisters Garden several times. The biggest problem I had was getting in there to harvest something fresh with the squash taking up so much of the ground space. Finally, I decided that I should just stay out of my Sisters Garden until the end of the season. One thing, the squash does so well with weed-suppression that there was little reason for me to be there for that purpose.
Yes, I sowed the Painted Mountain corn first and gave it a couple of weeks before the bean seed went in.
I don't have a mill but soaking dry corn and using a food processor works fairly well. I grew this flour corn 3 seasons but became a little lazy about making use of it. Having Cascade Giant rattlesnake beans is almost a must for green beans and dry, whether they are grown with the flour corn, or not. Winter squash, I have every year - Buttercup, for sure. They all grew quite well, together.
Make everything as simple as possible but not simpler. ~ Albert Einstein