Upgrade EV from 9.0 to 11.0 and migration from 32 to 64 bit Windows server

I need to upgrade EV server from 9.0 to 11.0 and migrate to new 64 W2008R2 server.

My thoughts for plan is as follow:

Step 1

Upgrade/patch current EV server to 9.0.1

Ensure EV Server setting Migration tool is available

Step 2

Install EV 10.0.0 on new Windows 2008 R2 server

Run EV Server setting Migration tool from 32 to 64 bit servers

Step 3

Upgrade/patch EV to 10.0.4

Step 4

Upgrade EV to 11.0

Would this be correct?

What are the challenges?

Do I need to add/remove any steps?

What would be the pre requirments in these steps from software Version to software Version?

How long would thius process take - especially the step 2 using the Migration tool?