Separate Database or Can Zoho Handle?

Separate Database or Can Zoho Handle?

I'm in the process of designing Zoho to meet the needs of our startup. As I look at my customer funnel; I'm going to have:

(exact customer state vernacular still needs to be refined)

Prospects  --> people who visit the website, download our app, and call us without enrolling at that point in time
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Leads --> people who take action from our lead capture channels and either sign up, or provide partial information
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Customers --> people who complete the registration and engage in our service
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Post Engage --> people who we have successfully and completely engaged with for that specific encounter

The design question I have, is that should I put all 4 of those customer states in Zoho? I'm considering splitting the Prospect state and utilizing a different "system" as I feel the top of the funnel will (or could be) so large, it could impact our ability to manage the remaining 3 customer states in Zoho effectively.

From a numbers/swag perspective, if we convert 1% of Prospects into Leads, we would have 100 Prospects for every Lead...and if we grow like I would like, the number of Prospects could be staggering.

Do most people tie their entire funnel into Zoho? Or are there design advantages to splitting "Pre-Leads" or Prospects into either another instance of Zoho, or a separate database altogether?

Thanks in advance!