Eddie, I would not put Sally Hansen nail hardener on your entire nail or even use it at all unless you are having trouble with chipping. Even then, I would only use it on the white part of the nail tip clear of the bed.
All of these things have solvents in them that are drying to nails and I think it is best not to use them on any regular basis.
The lunette at the base of the nail should be allowed to breathe. Don’t cover it with nail hardener. Instead, try massaging moisturizer or olive oil onto the nail, especially in the lunette area and cuticle. This helps prevent dryness and stimulates the nail bed where the nail is produced. Eat a healthy diet. The condition of nails and hair give an indication of overall nutritional status. For my nail health, I found that my nails were much stronger and more flexible when I supplemented with vitamin D3.
My nails grow quickly, so that wasn’t a problem.
The only thing I know that will help with growth speed is good nutrition and blood flow (stimulation).
When the sun shines, bask.
Classical Guitar forever!