I´ve done many flushes and pushed huge stones, some measuring over 2 inches, just unbeliable! Don´t worry there´s little risk in flushing.
Most people here follow Hulda Clark ´s protocol, which seems to be very good. I follow Mrs Chang´s protocol, from Sensible Health, as it uses less Epsom Salt and it works wonderfully
You can also use some bile mover and a stone breaker, this will make you feel better.
When we have gb attacks it means your bile is stagnant and your digestion does not work. So a bile mover (Chinese Bitter of Artichoke Tincture) and stoner breakers such as Gold Coin Grass or Chanca Piedra . All these will help you in between flushes.