For those that use a lansky or kme, what is the best angle for 2 blade broadheads?

That's determined by the grind on your broadhead. You want to sharpen the cutting edge not the shoulder of the grind. Use a black marker to know when you have the angle correct.

http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=000077

20 degrees on my Deltas

I like 25 degrees but I have the KME knife sharpener.

I find that for me with any two blade broadhead my sharpening angle is probably around 27 degrees. I take the bh and lay it on the stone the way it would be if I were sharpening it and then raise the angle just enough to clear the ferrule. This method of judging the angle has worked well for me in the past and it allows me to keep a consistant bevel without using a jig.