parent & child products ?

My client builds and supplies garden buildings, which consist of a core item of various sizes and a number of additional ‘bespoke’ options.
I have added options such as size and colour to the cart object on previous projects, but may need a different route, as the options can be product specific and the client would like the cart display to appear as follows, so that each option is itemised, as it would be in a quotation.

pictured is an example...

I thought about having the ‘child options’ as products in their own right, associating them with the parent product via a parentproductid field in the products table.
The objective would be, on the product detail page, for a customer to choose the product by size, in this case a ‘10x8 basic workshop’ and have all of the child products listed with their options.
The add to cart button would then add both the main product and its associated child products (if selected) into the cart on submission of the form.

I guess I have 2 questions.

Is there a better way to go about this ?
If not, is it possible / desirable to have 2 separate add to cart server behaviors running in series, (ie for the above example, I imagine I would have a simple add to cart behaviour for the parent item, followed by add to cart from recordset for the other items.
Grateful for any suggestions