Store > designer > kit
I move all folders for a kit into the elements folder so when I open it up I get to see all of the elements, then click on the individual folders to get to see papers, cards, alphas etc. I used to just have everything in the one folder but I find that I tend to choose a kit to use based more on the elements/theme I want to use rather than the papers. Also this way, to choose what papers I want I don't have to scroll the entire kit contents just to get to the papers.
When a designer moves store I just cut and paste the folder into the new store.
ETA the numbers at the beginning of the folder names relate to the order I have folders listed in my digi supplies folder, as opposed to having store appear just in alpha order.
For PC you can ensure that you get the kit preview icon to be 'on top' so that you can get an idea of the colours when viewing extra large icons. To do that you right click on your folder > properties > customise ... go to folder pictures section > scroll to find the kit preview >open > okay. Sounds complicated but only takes seconds.

I did mean to do a folder just of previews, but actually I just use the file explorer search on preview (and limit the search to store or designer if I need to for CT work or challenges).