Host ESXi upgrade from 4.0 to 4.1 and View 4.6

Hello everyone, I have a question in regards to upgrading my esxi hosts that are running a View 4.6 cluster.

Overview of my environment:

The 4 current ESXi hosts are running 4.0.0, 261974.  These hosts are UCS B200 M2 blades.

I'm needing to add a 5th host for capacity and purchased a new UCS B200 M3 blade.  The M3 blade will only support ESXi 4.1 U2 or higher so I can't install the same version running on my 4 current hosts.

My question is, what would be the best practice for getting the M3 blade installed and into my environment?

Should I install 4.1 u2 on the M3 blade and join it to the cluster with the 4 hosts running 4.0, then upgrade the remaining 4.0 hosts one at a time?

or

Should I upgrade the 4 hosts running 4.0 first to 4.1 u2 or u3 and then install and join the M3 host?

Also, please include any helpful upgrade documentation or links to, that would be great!

Thanks!