If you're set on using a Visa code, use the regular one. No restrictions against earning credit and the same discount. I think that the regular Emerald Club discount is the same.

https://www.nationalcar.com/en_US/ca...12-visa-1.html

Like I said before, the only benefit to using the Visa code is if you're using the Visa free weekend day coupon and using the Saphire's primary rental coverage benefit.