What is a good CRM for Personal Assistants?

Hello. I'm looking for a CRM that suits myself and my boss. To give you some background, we work in Visual Effects so we have High-value, low-volume when it comes to projects. We will only speak to maybe fewer than 300 people in a year and work on maybe 20-30 projects each year.

My boss is on the go a lot, he travels across countries and continents frequently, so firstly we'd like a CRM that has a strong mobile app or mobile web version that makes it easy to send, read and draft emails on the go. This is vital!

Secondly, it needs to have a function where I, the assistant, can sign into his CRM, and only see emails that we have selected out, so I'll be unable to see emails from his mother and sister etc, only a select group of clients that we can import from a CSV.

I've really struggled to find any CRM that does all of this. The main complications are the ones above. We use Salesforce as the moment which is great except the app/mobile web version is terrible!

I should also mention that I prepare emails for my boss for him to then check in his drafts before sending. It's vital that I'm able to save drafts like this, and be able to send emails on his behalf occassionally too.