Good call Aussy Made,
5x5 has more strength implications then muscle hypertrophy.
Higher volume, arouned 15 down to 8 reps, is a preferred zone for muscle growth. Higher volume, along with appropriate intensity creates greater microtrauma, which in short, will lead to greater muscle hypertrophy.
Higher intensity (such as 5x5) will stimulate hypertrophy, but its primary adaption will be strength. High intensity lacks the volume to create the appropriate microtrauma for maximal hypertrophy. What high intensity is primed for are neural adaption(s), such as increased rate of neuron firing, increased muscle recruitment by motor units per contraction, coordinated firing of motor units, all these neural adaption(s) are mechanism's of strength, which is best stimulated by high intensity lifts, such as 5x5, DC, HIT.
Muscle and strength do correlate, but it's not as linear of a correlation as you may think. Muscle is the size of the engine, strength is the headers/exhaust/intake/super chargers that maximize the performance of the engine.
For instance, pro bodybuilders look much stronger then powerlifters, but powerlifters can move more weight. That's because they spend most of their time training all those neural adaption(s), (whether they know it or not), while bodybuilders have much larger muscle, they train in a primarily hypertrophic range and lack the neuromuscular strength that power lifters posses.
5x5 training is great for strength training, but considering your goal with these supps are for muscle size, I would up your volume to between 15-8 reps.
I want to re-emphasize, yes you can hypertrophy with strength training (5x5, DC, HIT), all resistance training effects every aspect of muscle performance, from power, strength, hypertrophy and endurance, in that hierarchy from top to bottom, but it's how you tweak your routine (sets/reps/rest/frequency) that will "emphasize" a particular adaption, and right now, with the 5x5 you're emphasizing strength when I believe you want to be emphasizing muscle size (hypertrophy).
With that said, it's not to say you've wasted your time with the 5x5 with your initial cycle. Increased strength gives you a stronger base to lift at a higher volume with heavier weight, which will create a greater potential for hypertrophy, so your good.