I'd like to help but you need to explain a bit more about what your system does. I've helped build and manage racks and cloud installs. Some general stuff:

Downtime happens. It often happens when you move hardware around (say, you need another SAN or replace you switches. Cloud servers are very ver flexible; you can set up a parallel system and test it for a week. You can't do that with your own hardware without spending serious cash. The first time I rearranged my entire server set up, while sitting in a cafe, was pretty damned cool.

It also happens when hardware fails. With owned systems you have to drive to the colo in the middle of the night.

I suggest you build a minimal parallel system in a cloud and try it out. Try several providers.