Hi
The 3/10/10 is not so uncommon .
You find it on almost all first horse Bonus first version (alternated 10 stop . ) !
I see it also on Front castle .
you can find it on Watling also ! The Rol cherry front in 1938 .
That was nothing special , just an option .just a new idea after the great 3/5 , Mistery and other fun Idea .
Stephane