Jimmy

Congratulations on your acquisition of a Sansevieria or snake plant. You have one of the least demanding house plants in existence.  If I understand your question, you want to know how often to water and how much to water your plant. 

Snake plants take almost no water.  They also don't have the normal deep root system of other house plants. If you look at your plant, it has rhizomes that are actually very shallow and close to the surface.  The rhizome/roots probably only go down about 3 inches into the soil.  If fact, most snake plants are potted in tall/deep pots for balance and stability, not because the root system grows deep. Using your water gauge to  measure the moisture at the pot bottom will not give you the information you need. Instead, only insert your moisture meter or gauge down three inches and see the answer you get. When the meter reports "dry", water then. 

You report that the pot is 10" inches in diameter, but don't give the depth. So water, and then shortly later, use your gauge to see how much water is retained at the root level.  I would not water again until your gauge reports "dry."  You will have to play around with how water to put on the plant on each watering day.  With the information you have provided, I can't tell if 1 cup is correct, for example.  You can play around to get the roots wet, but not the soil at the bottom of the pot.

Some cautions:

1. Don't let the bottom of the pot sit in water. The water can actually wick up to the rhizome level and the plant will slowly rot. 

2.  Don't water unless the meter reports "dry" at the bottom of the root.  More snake plants die because of overwatering, not under-watering.  You may find that watering once every two, four or even six weeks is fine.  Five months may be a little long.

3.  If the leaves on the snake plant start to turn brown around the edges, they are getting too much water.  Cut back and read the meter.

4.  If the plant or dirt starts to smell "rotten", reduce the water and let it dry out.

5. If the leaves on the snake plant start to get "floppy", water a little bit more often.  That can also happen if the plants need a little more light.  Rotate your plant around periodically, so all sides get some light.

Jimmy, I hope that I answered a few of your questions. If not, feel free to reply back and we can help some more. Enjoy your plant.