So I've been doing a little research. I wanted to know what the sandals of the Bible might have looked like. This is one which I've modified for running. I made a 2 color prototype to illustrate the components. The 3/8" webbing is fixed per your measurements while the 1/2" webbing is adjustable to ensure a perfect fit.
Check out pinterest, facebook &/or instagram (Paisley Running Sandals) to see the hundreds of color possibilities I've created.
Graph paper trace picture required: With this picture I'm able to make a custom sandal for a very accessible price. (see youTube Paisley Running Sandals - Graph Paper Measurement). Just email me a picture of the trace and I can recreate your foot in my shop. Please just trace it on standard 1/4" graph paper.
I sew silicone elastic on the heel webbing to reduce slippage and hold tension through the tri-glide buckle.
The tread is either ~6mm Soletech, Vibram and Walkbase or equal. I sew a non-slip base onto the rubber. Memory foam is a $5 option. It adds a 1/8" bit of foam between the non-slip grip and hard midsole. As always it's cut to fit per your supplied measurements. Just tell me your application and I'll put the appropriate tread on it. It's completely resoleable over the years.
I have dozens of possible color combinations. See color swatch pictures of 1/2" and 3/8" options. If you're patient I'm always happy to match and order exactly what you're looking for.
The end result is a very stable, supportive & fashionable sandal. Wear them loose to kick around or tight to go for a run. They can even be resoled and reconditioned when the time comes. A truly sustainable sandal which will perform for hundreds of miles.
Please note, due to excessive shipping costs I typically only ship w/in the USA. Please contact me if you're willing to pay for international shipping. It's typically prohibitively expensive, but I'm willing to get a quote and pass the shipping cost to the buyer.