I find my pop up puts me in a good position for a driving/projecting bottom turn on a thruster set up but I need to shuffle my back foot back or sometimes both feet back a tad for more vertical/pocket surfing. I have no idea if that's normal or ideal.
If you were sliding out in a bott turn that's definitely a sign to get your back foot more back. I find that board much more likely to slide in quad v thruster set up.
I tend to prefer a thruster set up. For those size waves i would typically surf as a thruster, but the waves were pretty crumbly!