How much "Firepower" does my Managed vServer need? Please Help!

Dear Friends,

I have a few questions about wordpress hosting. I am a freelancer and I am hosting websites for my clients.

So far I have 20 Client websites that I am hosting for my clients.
Here are some facts about the websites I am hosting for Small and Medium sized Companies:

- 15-20 Client Websites
- No Online Shops, Mainly simple content Pages based on Premium Themes
- Bakery Visual Composer, Caching Plugin Avrg 15 Plugins per Site
- Average of 30-100 Unique Visitors for each Site per day

I have been using a reseller shared hosting package where the server specifications are not public. The sites are just hosted and it works, somehow. I assume that resources get allocated according to requirements. It is also a shared IP - which is why i am switching to a managed vserver hosting where I have more control and hopefully faster speeds.

The Server that I have purchased:

Managed vServer with the following resources:
KVM Virtualization
Intel® Xeon® E5-2680V4
8 GB DDR4 RAM (ECC)
2 Cores
60 GB SSD
RAID 10
Running on a reverse Proxy Nginx / Apache Setup
Plesk 12.5
No Root Access but SSH access is availible

My Questions:

Is the hardware enought to handle the Websites that I am hosting?
What is the limit for how many sites of this kind I can host on the server given 100 Visitors a day with the site specifications mentioned above?
How can I measure / find out if my server is doing fine with the load (CPU Monitoring, RAM Usage?)
Will I be better of having my own managed Vserver (Performance Wise) compared to the Mass hosting managed arrangement I had so far?

Thanks so much for your input!