Neil,
When I first looked at these pens there was an infinite variety of timbers, colours your fine tops down to larger pens is a true pen shape much closer to the pro factory made for ever which means it is the norm in shape, my guess is when they are displayed for sale you cover many designs timbers so potential customers then will do what any level headed person does look for does it fell right in the hand write legibly, ink flow fine enough to show clear figures etc. If you are a stylus user what an essential feature.
IMHO they are all winners and grinners.
Kind regards Peter.