Aquariums: Resealing question…

I am resealing a 120 gallon (~454 liter) tank with 0.5 inch (~13 mm) glass. I am in the process of cleaning up the old silicone now.

My question is:

• Do I leave the old silicone between the glass flush, like photo A?
• Or should the old silicone between the glass be concave, like photo B?

Thanks!