I think you two are talking past each other. You don't jump straight into 300 lb squats. You start with squatting with no barbell. Then you add an empty one. Then you add 20 lbs. Then another 20 lbs. In a few months, you have a lot of weight. This is going to get you stronger faster and safer than trying to do pistols (one legged squats) because you control the weight advancement. This is true for all weighted exercises vs body weight that I can think of. Pistols are hard and rough on your knee and the form is hard to get right. My back squat is over 2x bodyweight and is still find pistols hard and rough on my knees.