I owned an S500 optical for a while. Nice amp, it's a keeper, that is 250w and for memory used 20 bi-polar outputs per ch, and it has a big power supply, so it should have no trouble driving anything.
For optimum sweetness the heat sinks should be around 40-50c on a 30c day for optimum classA bias current. After a couple of hours warm up, that equates to NP’s palm of hand test of about 5 seconds before you have to remove them, so long as you don’t have hands like a brickie. Both side the same naturally.