alright, i've been sifting through sites all over and this is what i've come up with:
the only difference between the strains is the presence of red on the anal fin. gheitman, you are right. the interesting thing i found is that neither strain is completely "set". so if your lfs is selling double reds because that's what they bought them as, you get a bonus for finding any with triple red markings. when it comes to breeding, anything goes. you could have doubles or triples from either strain.