profection, for their "gourmet flavors", those under the heading of Specialty Juices, FreedomSmokeUSA (FSUSA) only offers a 50/50 blend. There is no other option if you want those juices.
I should point out, that some will order a Specialty Juice at double flavor and then "dilute" it with PG of the appropriate nicotine strength. You get more juice, cheaper, and you get a juice that is effective in cartomizers.
Even though some 50/50 mixes will work in the MF Cartos, it does shorten the life of the carto and will often encounter functional issues. For this reason, I do not recommend a mix that contains more than 40% VG, and, in my experience, hitting around 30% is the sweet spot for maximum vapor without altering the function of the carto.