You're going to want your maintenance staff to refer to SB 62-00-12 and 62-00-17, although older documents, they will provide guidance on what the definition is on a hot swashplate. Basically they say if you can't keep your hand on it, it's too hot.
If your swashplate is recently overhauled or new bearing installed, there are criteria specifically mentioned in the maintenance documentation that they should be following such as rotational drag.
Experience tells me that if the graphoil is applied to thick (exceeds two light crosscoats and is transparent, then the bearing will be tight and fail the rotation drag check, and thus will run hotter than it should.
So, your determination of "too hot" is based on keeping your hand on the swashplate.
Can't do it, ground the aircraft.