I have already limited the "warehouse" SSID to 2.4GHz, 20MHz channel size and made an optimized channel plan that keeps the neighboring APs on channels manually

I have already limited the "warehouse" SSID to 2.4GHz, 20MHz channel size and made an optimized channel plan that keeps the neighboring APs on channels manually chosen for minimum overlap. Anything else? Speed stepping? Reducing the wifi standard looses features like roaming hints and stuff like that, no?