Less then half sided with the Nine, if I had to guess, I would say initially, that less than 25% sided with them. Most of those 25% sided mainly with the priest because worse than today, priests were extremely few and far between - so when you had one, you clung to him, and they knew this.
So those 25% went the priest's way after they convinced the people of the priest's agenda, which either was, or was to be, sedeism - of which the then Father Sanborn was the ring leader.
As for Lad's number 1, there's another thread going on now still beating that dead horse, and for his number 3, the reason the Nine rejected the 1962 missal is because they did not believe the pope was the pope, and on that account the 1962 missal was null and void.
Looking back on it all, it seems to me that it was all about power. By that I mean the priests wanted it but could not have it because everything had to go through their superior +ABL, or at least that's how it was supposed to work.