Sorry, I didn't see your post back in April. Some how it never showed up in my feed. I have also gotten better results with more current and when I use my barrel plater setup, I can run out of current if I'm not careful. I have a larger power supply but haven't tried it yet. That being said, I think your plating times are too short and your current too high. When my plating results are really good, the parts come out of the zinc looking like chrome. Really shiny, silver plate and generally takes 5-8 minutes for a batch of bolts. I looked for a picture of an example but couldn't find one. What makes the difference between shiny and a flatter grey color is the particle size. You want zinc transfer at a rate that doesn't push too hard. When you add a lot of current you add a lot of "pressure" to the particle transfer. My understanding is that causes larger particles to be transferred, which means the surface isn't as smooth. So less reflective. Also watch out for unevenness in the zinc color and areas that blacken. That is also an indication that current is too high and burning your zinc. Do you have any more results? Did you get your chromates?