I bought ones which are wider and do much better and sit a few inches above. I can adjust each of the necks as needed. I have those thinner ones for my plants that need extra light but my early experiments showed they were not enough for seedlings once they sprouted.
Just a thought. These have worked well for me as I have no way to use a shop-type light or hang above. They clip on.
It gets 12hrs a day from an inexpensive grow light that I got on Amazon
i bought these lights from amazon and they worked fine for all my seedlings. I liked i could adjust height for different batches.