I have noticed that professionally done board always fill top and bottom with GROUND planes. As i have been making PCB board myself i find that having the top layer POWER fill and bottom layer a GROUND fill.On 2 Layer PCB what are differences between using POWER and GROUND fills as opposed to GROUND and GROUND fills?
Further more for Multi-Layer PCBs I have noticed that the stacked seems to be like SIGNAL GROUND POWER SIGNAL. why is that? wont filling the outer most layer with ground/power protect the signal traces more?