The layout builder will be a great helper for your server-side integration. You can get the HTML partials from the layout builder and convert into your view template and use them further. You can use the build tools for the assets and just include your assets with the generated partials HTML. Also, you can use gulp or webpack build tools to compile the assets upon sass/js code changes in the "src" folder.
Hi Sean, I understand my mistake. I tried to compare the default template (with no partials) to the partials. Its non-sense. If someone is interested .. I will do: - First use the layout builder to generate reference partials and keep them unmodified as a reference. - Turn them into twig templates - If i have to change one option, i can regenerate partials with the layout builder, compare them to the reference ones and adapt my twig templates in consequence.