Workflow suggestions?

I'm slowly starting to roll-out Zoho across our company and am looking for suggestions on ways to streamline the workflow. We run a small consulting firm and have a fairly limited number of clients at any one time, but lots of meetings with companies who are potential clients. Typical process is something like this - and how I'm currently thinking to do it in Zoho:

1) Potential client contacts us to arrange for a meeting or conference call - Create an event on Outlook Calendar and then sync to Zoho
2) After the initial meeting - Create an Account for the company and add Contacts
3) Decide if this is a company we might be able to help in the near term - if no, note account in someway that indicates we met and there wasn't an opportunity (custom field?)
3a) If yes - create a Potential and link to account and key contact
4) Create next steps task to convert potential into a client
5) Convert to a client - not sure how we note accounts that are clients in Zoho?

In general I'm curious about general workflow ideas, and if my ideas above are basically correct for how to use the system. A couple of more specific questions though.

Leads - Not sure how this would fit into a workflow, is a lead supposed to be a company or an individual. To my mind it seems that Potentials are leads, but I'm sure I'm missing a distinction.
Accounts - Are these supposed to be reserved just for paying customers/clients?
Potentials - Our "sales" process can be pretty long (as in it can take years to close a prospect) and it is very difficult to have an idea in advance on how long this will take, so I'm not sure what to put in for the closing date field. Also the amount we are paid is usually a combination of an upfront fee, and then a "success" fee that is a variable percentage based on the value of any deal we help them close. Is there a good way to track this in Zoho outside of a note field?

Thanks for the help. Enjoying the product so far, but trying to make sure I'm getting as much as I can out of it.