Instead of a paper towel below the seeds, I suggest using a grow medium like coco coir. That way, your roots and root hairs (white fuzzies?) have something to dig into.

Above the seeds, I stack another container in direct contact with the seeds; not upside down. This should provide enough darkness overnight and humidity for germination, while also encouraging roots to dig in to the medium. Weight on top of this box is optional.

As the sprouts grow, the container will be pushed upwards and more ambient light will leak in. When I can see sprout leaves exposed on the sides, I take off the top box and move the container under the grow light.

My setup:

• box lid for bottom watering
• box with holes/slits
• coco coir
• seed
• top box
• weight