I think if you are supplementing, then you will lose production. As you know, it's all about supply and demand. For me, I found that it was a lot better for my body and for the baby in general when I moved the feedings to every 4 hours. What happened when we nursed more frequently than that was that my babies were "snacking," and not getting any of the hind milk. In turn, I would produce less milk (because there was no demand for the richer hind milk), and the baby would be hungry again sooner (because she was only drinking the more watery milk). Feeding the baby less frequently, but really working to make sure she was eating a LOT (changing her diaper in between sides, undressing her so she was a little chilly so she wouldn't fall asleep), worked well for us. I'd feed her first thing in the morning, when she was very hungry, and really make her eat a ton. Then I'd get her to hold off on eating again until after morning nap, and again, really work on getting her to eat her fill. Then again, a big feeding after afternoon nap, and then a final feeding just before bedtime. That schedule worked great for us, and actually led them to sleep for a good long time at night as well.
In addition to that, you may need more fat in your diet. For me, whenever my milk got more watery and lower in volume, if I ate some cheese pizza, or a cheeseburger, my milk would become noticeably richer and there would be more of it. So, that's something to consider.
Good luck!