Adding stump grinder knives

[NCMau]

Last year I built a small stump grinder intended primarily for roots. I tool the idea form a Northern Tools model which was equipped with a 10 wheel and 2 sets pockets with 4 straight knives. It works okay for my purpose the way it is but I was thinking about adding 2 more sets of pockets.
My question is, should I add left and right knives or should I stay with the straight ones. I think that adding the left and right would probably be a better idea, but I like to have some inputs.

 

[svcguy]

The left and right bits might have a tendency to "snag" a bit. My grinder tends to be quite a bit harder on the left and rights (more unsupported tooth), the straight shanks seem to hold up better. I would say if you are happy with the cutting results you have now, it will just improve and be smoother with the added teeth. The left and right teeth are probably better for sweeping stumps, but may not be a good idea for roots. That's a good looking unit!