So I just starting using this plugin and everything

So I just starting using this plugin and everything is working well, but I have read about a few issues I might run into.

Firstly, the size of my email list. My server can handle my size without an issue, however, I think the plugin might be a problem. I need to send 1(one) email every 10 seconds...is there any way to make this happen?

Secondly, when I set up cron job to send 360 per hour...does it do this all at once? Is there anyway to change the "as fast as possible" setting before sending?

Now, irrespective of my server (which will handle the job up to 50'000 emails), will this plugin start being useless if I get to lets say 10,000 emails?

Any help and info is greatly appreciated.