So, I want to harvest in layers.

I have tons of buds, lots lower so what I am wanting to do is harvest different layers over time. I'm just wondering how I will go about it. Should I start at the top, wait a few days and them keep moving down the plant. Or should I just scrap the whole plan?

What strain is it?

You can do whatever you want. Sometimes I will remove all the top colas and leave all the lower colas for another week or two. The extra light will fatten then up more. But it all depends on your setup and end goal. It wont hurt anything except possible take the space of another plant that could flower in the area.