If you aren't comfortable reshaping ports, just match the outsides of the ports to your pipe and intake. Make a smooth transition from where you dremeled on the outside down farther into the port, but don't mess with the port windows on the inside of the cylinder. It's a pretty safe way to get comfortable hacking away at your cylinder with a dremel.
I would also go at least 16 up front, unless you have something smaller than a 45 on the back. I'm geared at 16x45 on mine, and it'll do a solid 38-39 (although yeah, it takes a while to get there.)