Like with setting up the Theme Manager, I tend to set-up my Design Assets and Masters. I want to establish a foundation of common elements, so that if a site wide change is required, I only have to do it once. I often drop in and detach elements from the Masters, which seems to work nicely. Page Titles sections and containers are a Masters item for me, I have a core file, which has the word PAGE TITLE on it. Then after dropping onto a page, I detach it and change PAGE TITLE to ABOUT for example. But having it as a Design Asset works well too.
As for what works best in the responsive environment is truly up to the designer and behaviors of the elements in the fluctuating environment. Utilizing all and any of the tools to size your elements gives you full control. The most common practice for me is to establish my grid within container/section and confine elements there within.
Most commonly for text blocks it’s percentages, images it’s percentages with max-widths, sometime but seldom min-heights, for containers inside sections percentages with max/min widths, and sections often vertical heights (vh) OR auto, max-min or fixed pixel height settings.
I hope this helps and good luck!
Teejay