I'm running 2x Z9 Mini off 1x APW3++

Will the one APW3++ be a limitation at all when running overclocks?

I do have another apw3++ But didn't bother opening it as it seems on paper to be able to handle it.

I'm getting 60 to 63c on the chips running at 637freq and fans on auto (3600).  What's everyone else's target temps and safe working limits?