All amp models sound different and all amp companies have their own sound that they are known for. I don't have any experience with Sunn amps.

A couple rules of thumb-

-punk usually uses lots of mids
-use a healthy amount of gain or whatever the amp calls it. Not enough to do metal, but for most punk you won't want a very clean signal.
-I find the bridge pickup is often the best for punk, although both pups together is also good.
-work on your technique. That will have as much of an influence on your sound as the tonal settings.
-for volume, loud. :)