What is the best time to create an PH Launch upcoming page?

I think 15 days before

To be honest! It's very subjective. But, I advise you to start around 20 days before the launch. Be active, connect, comment and provide genuine value to the PH family.

I don't think there is such a thing as creating one too early. By having one early, you have somewhere to send people to register at as you start to build your presence in the PH community and also start reaching out to your own network.

As early as possible

It is generally best to create an "upcoming page" for a product launch when you are in the planning and development stage of the launch. This will give you plenty of time to create a compelling page that accurately reflects the product or service you are launching, and that will capture the interest of potential customers. When creating an upcoming page, it is important to include key information about the product or service, such as its features, benefits, and pricing. You should also include a clear call to action, such as a button or form that allows customers to sign up to receive updates or to be notified when the product is available for purchase. It is also a good idea to include social proof, such as customer testimonials or media coverage, on the upcoming page to build credibility and trust with potential customers. Finally, be sure to optimize the page for search engines so that it can be easily found by people who are interested in the product or service you are launching.