Brewtalz tones are characterised by low headroom preamps/high headroom power amps. All you hear is basically the preamp. Bands like InFlames and Meshuggah sometimes even just plug in PODs into the PA live.
If you want low, low wattage for recordings, then even 1W is going to be too loud by the time you get to crank it all up.
I'd use the line out in one of your amps, or simply the master volume... Unfortunately because of the very design of metal amps, they're not meant to be pushed to 10 on the MV (hence the 50 to 100W ratings and the 50 to 100 preamp valves in :lol:)
Probably not what you wanted to hear, if your issue is volume. If not, then forgive me and I hope you find a compromise :)