Under the new (not so new now) Pro structure is there a limit on how many clients I can have.
Also, I pay for Gold for myself annually, is that necessary if I am also paying for a Pro Account?
There isn't a limit, you can continuing adding clients for an additional charge per client.
You Pro subscription includes Cronometer Gold features for your account as well as all your clients, so you don't need a Gold subscription for that same account.
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