Every time that I design a PCB I connect the TOP layer and BOTTOM layer to GND (GND pour). With this PCB I finally ended with an "isolated island", without possibility to use the TOP or BOTTOM layer as GND. I did added a VIA near the cap, but is it a good choice? And if yes, what's the raccomended dimension for the hole for the via?
This is the picture:
Update: PCB without the VIA and Eagle complaining: