I've been doing a lot of reading on biasing and I'm finding that there are lots of different statements regarding what to set as a bias point. In particular, for 6V6 power tubes (used in smaller Fender BF amps). I read in one place that a "safe point" for 6V6 tubes is about 27mA, and it can be raised from there by using your ears (sound) and eyes (watching for too much tube glow while playing) to taste. Another place I read a safe point for these tubes was 35mA. My understanding (so far anyway) is that the plate wattage absolutely should not exceed the spec for the tube. So a 6V6, being 12 watts max plate power dissipation (at least in most cases?) in a Fender BF (measured at approximately 420V plate voltage) to me means I would never want to exceed 12/420 = 0.0286A = 28.6mA bias current in this amp. Is this correct?