Hey for a 3k army should i keep my grail size at 12 or boost it to 15? what are the advantages or disadvantages for this increase in unit size? im playing against empire, vampire counts, and chaos mostly.

I believe that 12 is the maximum size for a grail knight unit. As it is I think12 is very ott at 3k let alone less points.

Cal.

A lance of knights should never be bigger than 12 models in my opinion, when there are more than that they become unwieldy and incredibly easy to outmaneuver.

If you want more grail knights I can only suggest taking the fay enchantress, the magic boost and a second unit of grail knights fit well into a 3000 point army.

If you don’t want to spend the points just compensate, get some questing knights, they are almost as dangerous as Grail Knights, and can be incredibly effective against heavily armoured enemies who don’t want to flee from you, which two of the three armies you listed can do.

More than 12 Grail Knights in a unit does seem over the top. Too many eggs in one basket... I think you need to put more points in other units to draw some fire away.

But on the subject of the Enchantress' Grail guardians... how do you rank them up? Doesn't the Enchantress' double-wide base screw up the usual Lance formation?

Yes, if you were to use her in the lance formation, it would make you lose one flank on the charge (she has to go in the second rank, and a flank knight can only attack if the model in front of it can). You would be better off ranking them up as 5 wide with her around, since the max unit size is 8 plus her base.