What are all these holes for?

I have to agree with the general concensus.
Pull the pins, seal with RTV, get it on as quickly as you can, and make sure the valve covers clear the intake so the gaskets can seal.
I hate leaks and seeps so this is the way I have always done it.

It helps to set the manifold on dry first to get an idea of how thick to make the front and rear beads of silicone.