[Jeikun]

It's called Forward Lean and, on my bindings, are specified by F# (1-5), the higher the number, the more forward lean. It'll make your thighs burn the first few times as it'll force you to squat more, but its useful if you dont like to keep your knees as bent as they should be. I keep mine set at F1 as I do park and need to stand up straighter so I dont end up landing on an edge.

I dont personally have a suggestion for you (even if you can adjust forward lean on your step-in's), but you should set it where you're comfortable but where your knees are forced forward a little.

as to your problem with your edges, your stance could be causing it (likely is). I'd say set your bindings to shoulder width, centered over the board and work from there. when setting your bindings, be sure to take into account the length of your boot (overhang). Also consider putting setting your back foot to a negative angle. It'll help with possible overhang and to keep your weight centered. I'd say probably -5 would be good. To sharpen your edges, you could either buy a $50 tool for tuning edges or you could call around to see what shops can do for you.