My first thought is that you may not need multiple power supplies to run your rig if you are drawing less than 1200 watts, do you have a wattmeter to check?  Your breakout boards will also support a 1600w psu which would be another option to stay with one psu if you need less than 1600w.  I have several rigs with 6 or even 8 gpus that draw less than 1200w.  You may need to tune the settings and under volt to get below the threshold for one psu.

I haven't tried the sync function on breakout boards, but I would assume you need to set the switch to sync on both for that function to work.  Its not clear to me the benefit of the reboot function as any motherboard will boot itself when the power comes back on if you set it to start on power on in the bios.  Since you have two different breakout boards, I would test the sync function  before hooking it up to your miner to verify that the pinouts on the boards are compatible.