Yeah, I'm sure that none of the professional strength and conditioning coach that Jones has worked with for the past half decade since he started training at Jackson's a half decade ago have any idea about how to build up legs as well as you do.
No, he doesn't, that much is obvious. My legs are way bigger than Jones' and I started as a 135lb chicken. Strength coaches know nothing about gaining mass.
One thing most people can't accept is that low rep squats are NOT the best way to make your legs BIGGER. That is why I add a set of high rep leg extensions and leg presses after squats with little rest between sets and stretch the muscle while it is still pumped with blood.
Furthermore, most people are so bad at squats they are almost useless. You see guys bending at the waist so bad they're doing "good mornings". Squats are a very technical lift as are deadlifts, a lot can go wrong.
Not to mention deadlifts add little or no size, the world is full of scrawny toothpicks that deadlift 700.
I would recommend front squats instead of back squats, if you do front squats without an upright torso you drop the bar. It's harder to do wrong.
Studies show front squats activate the quads more with less weight thereby reducing the chance of injury. Most people are lifting way more than they can actually lift, they need to drop the ego and work on perfect form.
Always use the lightest weight possible to get a challenging workout. You will get much stronger even though your weights don't look impressive.
That is because you are actually using your muscles instead of loading your tendons. Most guys are using little to no muscle to lift the weight. Then, one day, their tendons reach their limit. SNAP!