It sounds like you are doing very well. I would stick with this plan and go into your PCT as planned. You'll want to see how you recover. Recovery is a big factor in the final results. If you can recover fast and get your test back online quickly, you will have better luck holding the muscle you've gained. Plus, if you have gained so well on this cycle, there is no need to add more gear. The more gear you use in each cycle, the more you will want to use in the next one. The more you use, the more side effects and the higher the cost of gear. If I could make great gains using 1cc of test a wk, I would ;). 

As for a heavy bulking cycle, it sounds like you are on one! 17 lbs is a huge gain in size. Be aware that the more gear you use in a bulking program, the less chance you'll have of "less than moderate reteintion". Any of the traditional bulking drugs are going to lead to fluid retention. I've said it before, and I'll say it again...probably more than once...fluid retention can be your friend. Water weight doesn't have to mean that you look sloppy, with a round gut. I'm sure that a large part the the weight you are holding now, is fluid. And thats ok, if mass is your goal. Water helps muscle recover. It helps you push more weight. It protects you from injury. These are all good things when size is the goal. 

A good compound for adding mass, that has low side effects, is EQ. I'm sure you would do well in a 2nd cycle, running 16 wks of test 500mg and EQ 400mg. EQ will add some fluid, but not as much as other drugs. You should probably be ok with the same adex dose for that cycle and PCT will be the same as it is for this cycle. Remember, it doesn't matter what drugs you take, if the diet is right. As you gain this new muscle, you are going to have to eat that much more, not only to support your new size, but also to continue to grow. The bigger you get, the more you'll need to eat. I used to eat 400-600 carbs at one point, early on. Now I'm pushing 1000g lol