I've estimated dozens of projects over the years and in my experience the more you split it up the more the total estimate is going to be. You can even use this a tool to get more budget/time allocated to your project. Break it up as much as you can and no task is ever going to be smaller than 1 hours, but in reality you can do 10 of those tasks per day because if you bunch those 10 tasks together people will estimate 5 hours of work. But now you have suddenly got 10 hours to do the same work!