I'd not estimate time for that job until I knew how long it took to get my bad head off & what all I messed up while doing so. If it was me, I'd give myself a long 3 day weekend. That way you could do some detailing while the head is off, instead of just r & r (yank & slam) the new head in, which is what most shops would just do.
Adjust the valves after the new head is on, that way you can make sure you're at each cylinder's top dead center.