MKS Sylvians have a proper slot in the pedal cage. Feed the strap in through from the outer end. Put a complete twist into the strap, then feed it out of the pedal on the bike (inner) side.

Ive climbed big mountain and killer steep gradients using un-cinched straps. Some shoes don't work well in lose straps. My Specialized Sonoma cycling shoes can get no purchase on the pedals and slip out. Shimano leisure shoes have a better grip on the sole and work well.