You said you found yourself not stable. I just simply took the liberty calling it instability. My apologies. But what do you mean by you can't really recall about instability?
The other thing, yes maybe someone should chime in here on the issue of your wide stance. I just think it might be too wide but I don't have any solid facts to quote you unfortunately.
No worries man, you laid it out correctly. Im not a native English speaker so it sounded wrong. I only meant that i cant really recall what i was doing to cause instability. I didnt focus on my riding (i.e. if i was riding flat or not) until i started wiggling. At that point i remember lowering and stiffening my body to a more "squat-like" stance with my upperbody leaning forward. Wrong, i know, but that was my natural instinct to avoid falling.