Yeah sounds like you've got a directional board. You actually want a bit of setback (the nose is longer than the tail) when you're riding forward most of the time...
For stance angles there's many schools of thought. In general I think a DIFFERENCE of 18-27 degrees is a good starting point. So wanting to go to 18/-6 would put you right on the money at 24 degrees. I ride a -12/+12 but used to ride -9/+9... Back in the day I rode 0/+18 but it seems that nobody rides with a 0 deg back binding anymore! lol