Wow, someone is upset... so much to post three different times in a row.
Get whatever you think looks good. And to counter Ruckys statement, my Nissan fender mirrors are actually easier to see out of than my door mirrors. Non-Nissan units will be nearly impossible to see anything with though. I probably wouldnt search around for "JDM 720 fender mirrors" since Im pretty sure fender mirrors were not a thing by the time 720s rolled out of the factory.
Just look for fender mirrors you like and install those. If real Nissan, they should have spring bases... Im not sure if there is space for the bases in the 720 fenders. Earlier cars were designed with a cutout in the upper frame rails (hence the mirrors need to be in a specific spot for mounting).