Between my neighbor's garden and mine, we had most of the herbs covered. I didn't measure out the portions too closely, but I think about 1/2 cup of the herbs and about 3-4 tbsp of zest would work well.
I added them all in the last 5-10 minutes of the boil. I was afraid that any more time would create astringency. Most of the flavors came out great, but the lemongrass remained the dominant one over time.
Consider making 1 cup of spice tea ( 2-3 cups of water boiled with the same amount of herbs for 5 min then pull off 1 cup) and add it to secondary. I imagine it would have a similar effect. I hope you get a chance to brew it!