Well rad dont agree with you about horn being flimsy .It is not flimsy in any way if treated corectly .yes if you take all natural material out the centre it is thin like glass,but its not the way to work horn.
I also make thumb sticks with mahogany an rosewood,but still think horn makes the best one.
As for people not paying for quality i find thats not true,like single malt whisky if you buy a cheap , one not so clever, but try over15years and the differance is amazing.
Dont think it is a culture thing as you say,think that americans are very responsive to most things, the americans i have come across have always been very friendly polite and look into things before responding and would consider alternatives if offered to them.,But you would have to look into the market there i do know that a lot of americans go wild fowl hunting so things like ducks and drake head toppers would probaly go down well along with wading sticks.
But i do like the dog and the origInal checker work on the shank gives individuality and that with quality will sell
the size of thumb sticks oftern are slightly smaller normally they are the size from floor to the min .hieght you hve your arm held at 90 degreesand the armpit
You could pick up a buffalo thumb topper for 10$ so price shouldnt be a issue and once there polished set against a white boner spacer on a chestnut shank with the bark left on look good
All the same good to have reponse in any discussion
many thanks