
Your best bet would be to contact a Tricker's specialist such as Richard at the Shoehealer who has previously posted on this thread.
He has some basic fitting advice here:
https://www.shoehealer.co.uk/Tricker_s/Useful_Information/
but is also very generous with his time via email.
Exactly what I did too. Got answer today, they seems to be a bit big in size, he recommended a half size down.














