What Now?!

I have been knitting this "top" - which may end up being a "poncho" - and I've reached a point of decision. I think it's wide enough... But I'd like it to be a little longer. So what do I do now?!

I started this project because I was intrigued by the challenge of knitting stripes on an angle... I've been increasing one stitch on each end of every second or third row.

If I wanted this to be a SQUARE, I'd just reverse what I've been doing - decrease a stitch at the end of every second or third row. 

But I 'd like it to be a RECTANGLE.

So I think I have to continue increasing every other row on one end and decreasing an equal number of times on the other end.

To help me remember which side I do which, I've pinned reminders at the two ends.

I hope this is right! Then, when it's long enough, I'll decrease one stitch in BOTH ends of every second or third row!

Let's see what happens... Hopefully I'm on the right track!