MassPlanner will get glitchy if you choose to add more than 500 accounts to it. Its best to purchase a second licence if you need to manage more than 500 accounts.
Click Here - to learn how to install multiple instances of MassPlanner on the same server so you can manage more than 500 accounts.
For this current setup, the 32GB Dedicated Server from TurnKey Internet Click Here will work great for you. However if you think you will continue to expand 800+ accounts it would be best to get their 64GB Dedicated Server which you can add up to 2,000 accounts (4 installations of MassPlanner 500 accounts on each).
I can also provide you with instructions on how to save $25/month with their Dedicated Servers.
Click Here - To learn how to correctly Migrate your MassPlanner over to a new server.
Some say that database IPs (the ones you get from VPS/Dedicated Servers) are less safe than a good quality proxy. I also believe this.
Some will say that database IPs are safer than proxies.
Click Here - To see a list of Proxy Providers