No , I haven't tried policy based routing , would be helpful if you could point me to the docs
Also similar to my situation, I found Routing all external traffic from one specific machine to a particular WAN interface
Reading above I think above could do the magic but I lack enough knowledge on ip tables
Even routing a traffic from 192.168.1.100-150 thought WAN1 and 192.168.1.151-200 through WAN2 where DHCP only assigns address till 150 would be ideal for me