As DAWN has issues in my setup I like to try usteer. At first it looks more stable than DAWN but I cannot find much info how to setup it. I done the config got from OpenWRT wiki but perhaps somebody can share his usteer config with band steering and roaming support between APs for comparison.
Default one sends reports to lan network broadcast and handles all same-named AP-s across all nodes every 2 minutes.
If you want to change that you can use luci app or config/usteer lan network is in file beginning wifis are at the end, and micro-tuning parameters all across file.