I'm not 100% clear on what you mean by the following:
add variable shipping options for weight and dimensions on one hand AND flat rate on the other by customer selection. 
Can you please clarify that a little?
As far creating the Order and Order details table automatically, this will happen if:
1) You Create a database connection
2) In the checkout wizard, on the Store Order Summary page, you select the option to "Crate using Preset".
When creating a static catalog, yes, all of the individual pages need to created manually, With a dynamic catalog, only one detail page is created and populated with the correct product by filtering a recordset, using a dynamic catalog, you need to create a detail page for each product manually.
On each detail page, you will need to manually add the add to cart button. On the bindings panel, you fill in the product information like ID, name description, weight and price manually.
The getting started guide for eCart steps through creating static and dynamic cart pages.
