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OK then. The two dimmers in a box thing presents a problem. When you gang dimmers together you must derate them. Typically by 100 watts per added gang.
So two 600 watt dimmers next to each other...

It is completely true that dimmers get hot. "Too hot to hold you hand on" is a subjective term.

What is the dimmer rated? 600 watts or 1000 watts?
How many watts is it controlling?

No dimmer...