Hope someone can help answer a couple of noob questions...

How big is the total nonce range that a miner has to scan to create a valid hash

Am I correct to think that the total adjustment range a miner can make is to say (nonce + extranonce + timestamp), a total of (2^96)?

Or is there more to it?

I know nonce is (2^32) but what size is extranonce and timestamp are they also 32bit as I've suggested?

Also, what determines the starting nonce for each miner. I know there's a nonce provided in the block header, is this what gets used as the starting point or is that for something else?

Thanks for your help

G.