If you know the capacity of your measurement it is very helpful in selecting a gauge with maximum capacity. At least you should have some close estimate of peak reading. The best capacity to choose is probably between 30-70% of full gauge maximum capacity. You do not want to use too large a capacity to measure small force because it will be less accurate. However, it will be very safe from overloading. On the other hand you use with capacity near the maximum capacity it will be more accurate. However, it will have less room for safety from overloading. It all depends on how predictable your application is. These are the reason there are many capacity ranges to choose from. By the way, the gauge will start to display from a very small force applied, starting from less than 1% of full capacity.