Find the shoe(s) that fit...
And just keep buying variations of the same from Amazon or someone when the old pair wears out.
Sizing problem solved.
Outlet stores in the US are a good place to pick up cheap, shoes/boots/trainers in half sizes.
Just don't forget colonial sizes aren't the same as Imperial ones.
Didn't SAP roll-out of stock control at Levi's stores/warehouses in the US nearly bring the company to its knees?