Just here to echo some of the statements already made:
If we're talking Gyuto/Chef knife I would favor something around 240+mm long, around 3-ish mm thick, at least 52 mm tall but with good finger clearance.
For a petty or Santoku no input but I'll buy it
This will probably generate some...
Is there a way that we can make sure that Charlie and those that are putting the work in for this, receive one free of charge?
I would be fine with extra cost added to my purchase or going in on a side-pot for the respective parties.