Hi Diezel,
On your leg day, you mentioned single leg extensions aren't very effective for you. Try this. Instead of full range of motion (I know, I know... goes against most training advice), try going from full extension to about 135 degrees, or about half way down. This will keep tension on your muscles and should really hammer your VMO, that big tear drop shaped muscle on your inside thigh just above the knee. Go back to full extension and pull your toes towards your face and SQUEEZE! If you don't feel it, you must have amazing VMO strength!
Also, on your calves, I found the same thing true, I was able to do up to 5 plates on a side on the smith for reps without as much fatigue as I thought it would do. Since the calf is partly a stabilizer, try doing calf raises with a free bar. Just make sure to elevate your forefoot about 1.5-2 inches or so. Or try single leg calves holding a dumbell, also raising your forefoot a bit. You should get a pretty good burn.

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Single leg exercises are very good for strength and size. You work much more of your stabilizer muscles as well. Think about how you can make your exercises into single leg ones. You will reduce the compression on your spine, vastly increase your stability work, and crush your legs at the same time! Go for it!
One other tidbit, I like to get to my heavy sets as soon as possible, like you have done, but once you get there, THEN this is where your working sets start! Food for thought anyway.
Good luck in your quest!