Orange / Coriander Pale Ale

I stumbled across a recipe that was submitted by HBT. Decided it sounded like a refreshing summer brew and am going to give it a go sometime this week.
I am fairly new to brewing (this will be my 3rd batch), and have a few questions in regard to the recipe
First off as far as the Coriander goes, am I to use seeds or fresh coriander? I assume seeds because its calls for crushed coriander, but you know what they say about assuming. Secondly, can someone give me a rough estimate of how many oranges it takes to gain 2 ounces of zest, or suggest a way to come close to the correct amount? I do not have a scale to measure it.
Lastly, This is an all-grain recipe, since i do not have the means to all grain brew, my LHBS suggested replacing "9 lbs. Maris Otter Malt" with a combo of 3.3 lbs of both pilsen light and munich malt extracts.
Like I said, new to brewing, and want this to turn out as best it can, so all suggestions greatly appreciated!

Thanks! - Dan

I'll bet you the answer's somewhere in this thread ...

https://www.homebrewtalk.com/f66/cascades-orange-pale-ale-84558/

It absolutely is a great recipe, BTW.

It took me about 9 valencia oranges for 2.5oz of zest. This was for an orange brown ale and boiled 5 minutes.

Here is a long thread about a blue moon clone:

https://www.homebrewtalk.com/f12/blue-moon-clone-65328/

Blue moon sounds similar to what you're brewing, and there is a great amount of discussion in that thread about amounts of coriander and orange to add, and whether to use orange zest, or peels, or just orange extract.
Long thread, but might give you some ideas.

I brewed one of the final recipes in that thread, and the coriander/orange were just about perfect.

Thanks Nohup, I'll check it out for sure, although blue moon is a wheat beer, this recipe is an ale so I don't think they'll be to similar. I wouldn't mind brewing up a blue moon clone anyhow, my other choice was going to be a blood orange hefeweizen recipe from Sam Calagione, so I'm sure a mixture of the info in the thread along with that recipe could be the makings of a great brew.