Hi and Welcome the Knitting Help.
There are several different increases as you've discovered and just about everyone has a favorite, go-to increase. You can take a look at the ones shown under the Free Videos tab at the top of the page and try some of them to see which you like and which one works best for you but M1A is a good general increase and it'll work well in this situation. It occurs between stitches so it's easy to maintain the correct stitch count.
http://www.knittinghelp.com/video/pl...1-left-english