This modification will give you a little stretch as you work your core and balance. The lower the surface, the easier it will be. :)
Nail The Form
Keep weight in the heel of your planted foot. Your back foot should feel more like a balance aid: keep the weight in the front heel. (wiggling your toes is a good sign the weight is in the right place)
Your front knee will likely stay on top of, and not past, your toes. If you’re taller, it might edge forward naturally, and that’s ok! As long as your weight is in the heel, it’s fine. :)
I like to keep my back knee right under my hip, but you may find it more comfortable to create more distance. That’s cool. Depending on your hip flexibility, play around with the angles. :)
As you twist, use your core to stabilize yourself and focus on keeping the weight in the heel. (notice a HEEL theme here?).