If you're making that many it may be worthwhile to invest in a tool. I prefer the Deb Tucker Wing Clipper. It gives me perfect results with just slivers of waste. If you don't want to buy the tool, watch her video on YouTube and then try to adapt it to a ruler you already have. I have done that before I had her ruler and gotten good results, just not perfect like using her ruler.
As far as pressing, I press toward the "sky" part also.