So sorry man, I thought I subscribed to the thread >.<.
I begin by activate GWA, increasing the muscle size in my right leg. The large concentration of water, increases it's weight, causing it to lower abit. I focus on the size of the arm, memorizing it. I focus on its weight as well, while holding it for several hours.
Once ready, I deactivate GWA, while focusing my water chakra to increase the muscle size of my left leg this time. I remember the feeling of my right leg when GWA was activated, I use this to re create this feeling without it activated. I add more and more water chakra increasing the size of my left arm.