Virtualization and Containers...

I am working on a project in which I am considering using containers.

A few questions though:

1. Since my server will be a VPS, how are Ubuntu containers affected versus a bare metal server?
2. Is there a rule of thumb for the number of containers that can be used efficiently?
3. Is there a rule of thumb on how the host server should be configured versus the number of containers needed?
(ex: with 4 containers, the host should have X mB of ram, X mB of storage, etc.)
4. The containers will be used as media servers, ingesting rtmp streams and outputting HLS.
(I am aware of bandwidth issues)

Any other concerns I should have in doing this? Am I insane?

Thanks,

Ray