100 tips? Recommended by whom? The problem with all tbr systems is that they need to be calibrated regularly and most importantly, at installation. It's all very well a company saying that their system is accurate to whatever when it's produced but after it leaves the factory it's then subjected to being thrown about in transit etc, etc, which can alter the calibration. Calibration needs to be done correctly with a very accurately measured volume of water otherwise it's pot luck. Done properly, this doesn't require 100 tips. If you can get to within +/- 5% of a 5" then you're doing well. AWSs are great but most are probably inaccurate because they are rarely re-calibrated regularly if at all. This goes for temperature as well as rainfall.