Be careful with the advice that is being offered. With people suggesting temp ranges from 82-96 someone is feeding you crap rather than fact. Toyota will be able to provide you with the temp range for thermostats for particular engines and I would be following this specification. Remember that Toyotas tend to run in the 82-85 range, although there are some variations. I still get to stare at the 1ggte sitting in the corner with a blown head gasket because I followed someones advice to use a Camira thermo swith for the fan (96 deg).
The message that I am trying to get across is to be real careful of advice that you get from internet experts and be careful when you respond with opinion as you could cost someone heaps.