Ketogenic v. modified atkins-efficacy?

Hi. We are at the point where we need to consider ketogenic diets. We have several failed meds, brain surgery, and are considering a new med with a pretty serious side effect(losing peripheal vision is a possible side effect). Seizures remain, and his cognitive declines are troubling. At this point, we are willing to try anything. I understand that the modified atkins is easier to implement, but at what efficacy cost? While it may be easier to do the modified atkins, we are willing to do the classical keto if the success rate is that much better. Any info on this? Sources? Thanks!