X2 is the way to go. REALLY nice, translucent color...and a bottle will last forever. TIP: Put a stainless steel nut (make sure it's stainless steel!!!) into the bottle to help completely mix the colorant (that applies to any brand colorant). The pigment in colorant is heavy and will fall out of solution and needs mixing in.

For x2 I use 1 drop per oz of plastic as a general rule of thumb.

I generally add heat stabilizer after the 2nd reheat on light colors.