If you put his legitimate max squat at 315, he should be working through sets of 250-280 to bulid up.
So move it up a bit fuckwit.
The point still stands - you always try to set goals and time limits that have you avoid long periods of time, slow growth, and consistency. This jives with your impulsive, neanderthal mentality.
You could do a 405 legit if you put in the effort for a year. Depth and form wouldn't be an issue.
With the amount of hormones you have taken, it should be a minimum.