Addendum: I said I don't want to "get big" and then mentioned getting mass gainer; I just try to make sure I get a good amount of carbs in post-workout. The rest of the day I try to keep the carb content lower with the protein content higher.
My goals are simply a stronger core for Judo/BJJ; I think I cleared that up recently, my apologies if I didn't.
As for my recent mention of mass gainers, those are different from regular protein shakes in that they actually have a metric fuckton of carbs AND protein. However, after reviewing cost and content of a few bigger name brands, I think I will stick to the meal replacement bar pictured earlier in this thread.
Why don't you just eat people food and take a vitamin?
But seriously, I do. The only time I eat non-people food is directly after a workout, and if my schedule wasn't so tight I would make a meal then as well.
A twenty-rep bodyweight squat is a fine medium-term goal. However, I agree with CoffeeFan that a 5x5 or 3x5 routine is best for you right now. Get your 3x5 squat to well above bodyweight, then test your bodyweight reps to see if you can hit twenty. A twenty-rep goal doesn't mean you have to do twenty rep sets to achieve it.
I wouldn't forget the deadlifts while you're at it. Check out Starting Strength.
And I highly recommend a barbell. Smith machines are not the same.