Only blue and clear Fiocchi's in my AO, can't help, but if like many other makers, they are likely the same inside. Cut one apart and see for yourself. If the same, load using Federal Fold Medal data or most any other straight wall data.
Look carefully at the inside of your red Fiocchi hulls before you start loading them, - some of them have taller base wads than the traditional 7mm base wads. Not only that, some of them, or at least the ones I encountered, had varying height base wads which can leave you with an unwelcome surprise at the shot drop station (when shot overflows). I handed up pitching all my red Fiocchi's, and like mentioned above, I only load the clear and blue Fiocchi hulls (with the 7mm base wads).
While Hodgdon does publish data specifically for the Fiocchi hulls and the 12S3, it's limited to Rio G-600 primer, and the Fiocchi Fio 617 primer (which you can't get). I myself exclusively use the Rio G-600 primers, so that data is useable.
However, and as mentioned above, it is common to just use Federal Gold Medal data (or any other straight-wall data). That said, also make sure to use either an OEM 12S3 wad, or the Claybuster CB2118-12 which is a good performer. The Downrange DRF3 is going to cause you performance headaches.
18 grains look to be a good starting point. The Fiocchi hulls have a slightly larger primer pocket, however, it's been my experience that the Winchseter W209's have enough of an interference fit in once-fired (clear) Fiocchi's to not be an issue.