Just setting the bias to a number doesn't tell you anything unless you know the plate voltage too and figure out the power dissipation equation. If your amp has ~560v like my 200S does, and you were using KT88's, then your 47 on the bias would be a little low. If you were using 6550's, it may be a good spot to set it, but you need to know the plate voltage also. Please be very careful if you don't know what you are doing ehre, or take it to the tech to set the bias correctly.
There is a way to test the taps accurately, but it requires a signal generator and a couple multimeters. You can use a multimeter set on resistance and get a somewhat close approximation sometimes. An 8 ohm tap might read at 6 ohms for instance, but it doesn't work on all transformers. Sometimes you can also tell by the color code. I can't recall which color is which, but they were somewhat standardized. You may also be able to tell by looking at which tap the feedback loop is connected up to. You would have to open the chassis to find this out.
The Sunn circuit can tend to be very bright, especially for guitar, and that is just the nature of the amp. I would suggest that the bias may be off from where it should be.
