I open and close my store every year, due to close in a few days until November.

When I re open I have all my listings ready in TL in files named the same as my store categories. I then open the store and once I have updated and synced TL I bulk edit all the listings to change from 7 day to 30 or GTC and then edit each category to move it into the correct store cat.

It only takes about an hour and then I am up and running and getting maximum use of my store fee.

If you don't already have any items ready to list then I would do as above but perhaps open the store once you get about 50 items ready and then add more over time.