Salt this beer! But how much?

Ok, so i am brewing a batch of mexican light lager for a friend of mine.


5# 2 row
4# flaked corn
1/2# rice hulls
1tsp amylase enzyme

1/2 oz cascade(60 min)
1/2 oz cascade(flameout)
Safale s33

Now i know these particular ingredients aren't to style, but he just wants me to brew it, and i don't wanna have to drive to the LHBS.
Anyways, I wanna try salting the batch since i know he'll be shoving limes in it.
But i cannot find anywhere about actual amounts of salt to add. Even for water profile, not just flavor. I've never added salt so i don't have a reference point to start with, any suggestions?

Check Palmer's how to brew. This little calculator has come in handy for me.

http://www.howtobrew.com/section3/Palmers_Mash_RA_ver2d.xls

I would say wait until the end of fermentation before you bottle. Get 8 oz of your beer and add salt to taste (measure it!). Then just scale this up to your five gallon batch.