those warwick heads are notorious for having no hedroom, they still seem to do ok on ebay though because of the warwick name, if cash is an issue see if you can source an old peavey, super cheap, loads of head room and built like a tank but heavy (i think there is on here for sale somewhere
i used to work in a shop that had he full range of warwick heads and even the supposedly 1000w one was poor in percieved output volume compared to most other brands in my opinion
which cabs are you using?