I needed more of a marinade and also found the quantities listed to be insufficient. I adapted the recipe by doubling the quantities except for the pineapple juice. I combined all doubled ingredients in the bowl as specified and mixed well. I didn't bother with the pounding of the chicken and instead trimmed the fat, rinsed the two pieces I was preparing and then put them in a ziploc bag. I poured the marinade into the bag and then added the pineapple rings. I'll let it sit for about four hours and then grill them.

I agree with Jonathan, no need to pound the breasts, but I would not add the pineapple with raw chicken and would reserve some juice. Never baste with marinade that has touched raw chicken. The pineapple juice is great tenderizer.