Just ordered a GG6. Never used a DA before and will just be using it to apply sealants. Been reading a lot on here but I'm still not sure what pads to order. Do I want 6 1/2 or 7 inch pads? Which pad brand is the most durable? If it matters, I'll either be applying Zaino Z-2 or Duragloss 105/601 to a few vehicles.