Hi there,
If you’re just looking to do this on one page, then I’d recommend using the following implementation provided in this knowledgebase article – http://support.swiftideas.net/knowledgebase/replicating-the-demo-naked-header-example/
If you only want the overlay header on the home page, then it’s best to do that.
In terms of extra spacing at the top, check out the following advanced tips for the page builder, we’ve added some helpful classes that you add to the extra class box to remove margins/padding. Also be aware of the top / bottom spacing that you can disable in the page meta options.
http://dante.swiftideas.net/documentation/#swift-page-builder (Advanced Tips)
Hope that helps!
– Ed