I can only approach this question carefully, as I'm not a "QP" or never was SF, but I can tell you that my lowly 6 years with the 82nd Airborne were not enough for me, at the time, to have prepared myself for the rigors of SFAS or the SFQC.
IIRC, at the time you had to have at a minimum 5 years of operational experience in an Airborne unit, in a combat arms MOS. This would have limited the supply of candidates to only the 82nd Airborne, the Ranger Reg, or 173rd Airborne. Perhaps someone that was Airborne qualified and with 101st would have been able to apply, but I'm out of my depth, therfore one of the "QP's" can answer and make corrections to my statement. I'm only speaking of the early 80's when I was on active duty with the 82nd Airborne.
Several of the men that served with me, E-6's applied, some finished SFAS, some did not, and came back to the 82nd Airborne with thier tails between their legs. These same men were the top of the crop of our Battery with many years of Airborne and combat arms experience. Just goes to show that even an experienced Airborne soldier is not an automatic approval for selection to the SFQC. Point being, that there is no easy way to get there, and I highly doubt that I had what it would have taken to meet the grade, even with 6 years of combat arms experience entirely with an Airborne unit.