The hard truth is that no one can tell you how much to do. You will have to experiment on your own to find your "sweet spot" - Mine seems to come when I'm doing it 4 times a week. It allows me to gain strength and lean mass, while keeping fat gains to a minimum. This is NOT during a diet or prep phase, simply during an "off season" or "clean bulk" phase where the pedal is to the metal on gaining muscle.
What I can almost certainly tell you is that doing exclusively cardio for 20 hours a week isnt the answer, and doing exclusively weights isnt the answer (FOR YOU, based on what you have just told me) - As always, the answer lies somewhere in between... Or maybe you need to do 6 hours of weights AND 10 hours of cardio IF your goal is to have a lean AND muscular physique... Unfortunately this takes hard work for long periods of time (The rest of your life, or for as long as you wish to maintain that physique)
It sounds like your goal AT THIS POINT IN TIME is to lose some body fat, and cardio can certainly be a part of that picture. I would really focus more on your diet than anything else if that is not squared away. Eliminating the shit and adding in veggies alone will do wonders for your physique in a matter of months. A 36 inch waist is at least a small hint that you may have dietary issues that can easily drop 2-3 inches in as many months with NO worry as to doing any cardio.
From there, once you can lose a steady amount of fat without doing any cardio, you should gradually ramp up your cardio as needed to continue burning extra fat.
PS - I absolutely hate doing cardio, so my mentality is "how little of this can I do to get to where I need to be?" - So if you LIKE running, you may want to approach it differently. Me? I would rather keep my diet ON POINT and keep the cardio to a minimum, you may be different. We all have to figure out what we are willing to sacrifice to achieve our goals.
PPS - I'm also a body builder so my approach also assumes that you are training in that style (4-5 days a week with weights) consistently BEFORE cardio even becomes an issue.