When you buy a drill bit set, it most likely will come in a storage case. This case will help you figure out which size bit you need to use. When drilling holes for a pilot or lead hole for a nail, find which slot in the bit case the nail will fit in. The next size down is the bit you should choose. When drilling a pilot hole for a screw, you need to choose two bits. One for the starter hole and one for the pilot hole. Find which slot in your bit storage case the screw will fit in. That is the size of bit you should use for the pilot hole. For the starter hold, use the next smaller sized bit.
Moles don’t usually eat plant matter, focusing instead on insects. However, rodents such as mice and voles use their tunnels like a subway, and they do eat roots and bulbs. As you plant, mix products made from crushed oyster shells into the soil surrounding the bulb. This makes for tough digging for the rodents, and they might be induced to look elsewhere for a meal. Some gardeners resort to planting bulbs in little cages made of hardware cloth (wire mesh) to keep critters from munching on the bulbs.