pureoldsound wrote: ...I am not a pro but it seems that there are just a few things without changing the design to much that you can do..... 
there are actually quite a few.
the size of bypass caps in relation to cathode resistors affects LF rolloff.
the size of coupling caps (HF rolloff)
where you have more or less gain, affects where in the chain distortion first appears, as do biasing closer to center, or closer to saturation in a particular stage.
the size of a bright cap (if at all).
NFB (if used).
the values in the tone-stack will affect frequency, amount of boost/cut, and the shape of the response curve at "neutral" settings.
so far, we're mostly talking about component 
values in the same circuit.
we haven't even mentioned the choice of iron or tubes yet.
pureoldsound wrote: ...About the each amp being different, well he might have tweaked the first ones, but after orders pilled up I am sure that everyone got a standard circuitry with what he thought was the best mod.  (don't hold me on that it is just what I think)  It will be so time consuming tweaking each amp per customer request, that he would have not have time to finish other amps.....Maybe people got the basic amp and then thought well I need to address this part and that and then he might have tweaked it . …
that DOES make sense.
another 
possibility, is there may have been 
some variations according to what the customer was planning to use the amp for/with, and what he knew from past experience, worked better in those applications.
the only way to determine if there is a grain of truth to that would be to talk to some 
first owners of Wrecks, and ask if there were any questions from Ken on what the owner was planning to do with the amp.
but since he probably swore all of them to secrecy, we'll likely never know.   
 
 
pureoldsound wrote:....Well I think he design each amp around what he though had the best sound possible, after reading a bunch of threads and columns, he kind of preferred Celestions.….
with nothing else being certain, that would be a reasonable direction to go.
if you knew 
his favorite configuration of size, model, and cabinet (as well as how many cabinets)  you could dupicate this. 
this seems to be the direction of this thread, and 
i'm not saying it's a bad one.
just that it 
might not be universally applicable.
cheers,
unk