KT-88s and 6550s are supposed to be a little different. The 'KT' part stands for 'kinkless tetrode' as there was supposed to be no 'kink' in the linearity curve. These days though, KT-88s and 6550s are pretty much the same thing.
The B&W is a Voltage Paradigm device, see:
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php
for more info.
What this means is that the amplifier you use will need some feedback in order to work. The Wolcott is going to be the epitome of this- it behaves as a true voltage source using Voltage Paradigm rules.
The B&W is a Voltage Paradigm device, see:
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php
for more info.
What this means is that the amplifier you use will need some feedback in order to work. The Wolcott is going to be the epitome of this- it behaves as a true voltage source using Voltage Paradigm rules.