Auto-Target - Model Building and Activity Duration

In their documentation, Adobe suggests the following guideline for determining sufficient traffic when a a Conversion metric is used for Auto-Target

"1,000 visits and at least 50 conversions per day per experience, and in addition the activity must have at least 7,000 visits and 350 conversions.:

My question is, in general, if these requirements are met, how long should it take the models to build? More generally, there is a calculator for Auto-Personalization Activities - can one use this to estimate a sufficient duration for Auto-Target or is there an alternative calculator that will work?

Thanks