Mounting to Fence Posts

I have 8 of the eg4 Brightmount racks and we have a farm and a bunch of 8" treated fence posts. If i drove them into the ground with a pto post driver, do you all figure that would be sufficient mounting surface?

An 8” post driven in far enough should support MULTIPLE panels, an entire small array. But depends how far you drive it in, and into what soil. I couldnt be more specific than that because while ive observed all kinds of fence post failures of various kinds living in the country, i dont have any vocabulary to go with it. ‘I know it when i see it’ ?

Yeah, the plan is to drive them 36 to 48 inches and use 1 post per leg of the brightmount. 32 posts in all.