You'd be better with the next side down (medium) but will get away with this. Have a look at the Union binding finder in the support section of their website.
eu.unionbindingcompany.com
The boot looks centrally located on the footbed. You can slide the rear heel cup forward into the chassis frame which will push the toes a little bit forward on the gas pedal.
Not sure with the Strata, you maybe able to move toestrap mounting location back to the rear notch which will give you a better fit and the ability for a longer toe strap length . However now looking at chassis design on the Union site it appears with the Strata it has a single fixed mount position.

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The boot looks centrally located on the footbed. You can slide the rear heel cup forward into the chassis frame which will push the toes a little bit forward on the gas pedal.
Not sure with the Strata, you maybe able to move toestrap mounting location back to the rear notch which will give you a better fit and the ability for a longer toe strap length . However now looking at chassis design on the Union site it appears with the Strata it has a single fixed mount position.