XPS 13 9380, choose between 8GB and 16GB RAM model?

Hi,

Where I live the new Dell XPS 13 9380 (2019) is available with 8GB or 16GB RAM. How do I choose between those, like when does 16GB really give you a benefit in a laptop like the XPS? Anybody has experienced or tested this in practice?

For example, will you see benefit in Chrome which uses a lot of memory? I usually have 30 tabs open (3 instances with each 10 tabs) so will 16GB memory make a difference there?

Also, for video editing of 1080p videos, so not 4K, will 16GB be much faster than 8GB? I use Videopad for editing and sometimes with my older XPS 13 with i7-6600U and 8GB RAM it feel it's a bit sluggish. Or is the Intel HD 520 GPU the bottleneck? New XPS comes with Intel HD 620 so not much better I suppose.

An example of how I feel Videopad is slow is when adding a (long) movie clip to edit like a 7 minute 1080p mp4 file (934 MB in total size), it first wants to cache it showing me a green progress bar in the preview bar that takes forever to load. When I move my mouse over the progress bar, it says "to speed things up, we are caching your video. Watch the preview, after this progress bar is finished." The strange thing is that I can still start editing even before the progress bar is finished I think, not sure I could do everything however, but why does this progress bar take forever like minutes to load?

When looking in Task Manager neither my CPU or RAM (8GB) are used to its maximum, so why is this progress bar so slow? Is it maybe my older i7-6600U processor or what exactly? And why does it seem that i can still start editing even before the progress bar is done, even though I am not sure I could do anything?

Anything else with which you will see the benefit of 16GB of RAM over just 8GB?

Concerning i5-8265u and i7-8565u, are these equally good in real life or when will you see an advantage with i7 over i5?

Thanks in advance for all good feedback!