hmmmm.... saddled up with the "more is better" camp.
If you're not really pushing the power amp, then you've not truely experienced the GK growl. From an experience stand point, get only what you need. Again, I play the 700, and I can barely get it to hit the rails with the current situation I'm playing in. Read this from an interview with Bob Gallien:
"When a power amp puts out as much power as it is capable of producing, that is referred to as "hitting the rails." The way our amps go in and out of the rails is very different to how other manufacturer's amps react. Sometimes you will hear guys talk about "the G-K growl." If a bassist is used to playing an 800RB, he'll know exactly where he needs to place the controls on his amp to get that G-K growl. If he then moves to the 1001RB-II which puts out over twice as much power as the 800RB, he'll have to play his amp much louder to get that same type of growl. I have found that this is one of the biggest things that bassists have to learn in moving to a more powerful amplifier. If you want to maintain the classic G-K growl and don't need to play at loud volumes, then you definitely want to stick with a lower powered amplifier so it is easier for you to hit the rails."
The entire article is here:
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Again, the GK heads are a great value. Get what you need now, and then move up as needed later. And think of it this way, you'll have a great back up head for later.
Ljazz