I personally wouldn't recommend the high agi builds. Speed is nice, with 5 PS you might still be able to deal some decent damage (with a heirloomed pike!), but all that agi won't help you at all in a 1v1 situation, where you will simply glance with that little PS.
Consider a 21/18 build, or even a 24/15. Pike is a long weapon, speed is generally secondary to damage for it. With 7 or 8 PS you will deal very considerable damage and this will also allow you to defend yourself in a 1v1 situation with it, with good enough timing.
I had a 9/30 build last generation, with a deadly pike. It was horribad. Rolling a 21/15 cav/pikeman build now, it is so much better.