Try Awseomeminer firmware it's vnish firmware with added features, using their version you get to use their monitoring software for free, which I think is very useful for your set up.

What I would do is set a high profile, something 20% below the PSU's limit, and then use the monitoring software to play with the mining profile based on the temps, here an example.

If max chip temp is < 85 ( keep 52th profile)
if max chip is > 85 , ( change to 50th profile)
if current profile is 50th and chip temp is >85 - (change to 48th profile)
if mining uptime is > 2 hours and temp is below 75c and profile is 48th (change to 50th)

These are some of the many things you can do with Awseomeminer firmware, you get also get it to send you emails or telegram notifications for when something happens, the initial tuning for each profile can take a while, but when it's done once, it's done for good and switching from one profile to another will take only a few seconds, this way you can run your miner at lower hashrate during noon when it's hot, and higher when it temps cool off a bit at night.