As near as I can tell, all of my figs have FMV already. It slows their growth when they're small, and/or early in the season--although it's hard to say for sure, because most of them are only starting their second season in the ground, and since nothing has leafed out yet, I don't know how much leaf distortion will appear. But, based on last year's performance, the pattern here seems to be varying degrees of stunted growth and distorted foliage from the time a cutting develops its first leaves up until it's about 18 inches tall, and probably the first flush of growth each season afterward. Then, the subsequent leaves start developing normally and it doesn't seem to matter.
My Black Madeira has been so stunted by FMV that the longest branches are still only about a foot long, all arising from near the base, and it did not start to grow rapidly until late last season, so I'll be interested to see how it does this year. But, if it follows the pattern of my other figs, it will be doing well once it gets a little bigger. At least in my yard, size and a more extensive root system seem to largely overcome the significant impacts of FMV--but only time will tell for certain.
What I'm hoping to find out by grafting material from slow-starting, FMV-infected varieties such as UCD's Black Madeira or Ischia Black onto a vigorous, well established, but doubtless FMV-infected tree like my UCR 135-15s, is whether they will grow any faster and better than simply trying to start them from cuttings. I'm guessing they will do better, and will overcome the effects of FMV faster, but I won't know until I try it. I'll let you know what happens.