If you are going to use the run stand a lot and you need to depend on the numbers for carb calibration or tuning then I'd get dual gauges. Put a separate gauge on each side of the engine. It will cost a bit more money but then you'll have a redundant system. That allows you to check the gauges to see if they are reading the same and it allows you to keep running if one gauge goes on the blink. Use the same exact make and model gauge on each side so you can swap O2 sensors from side to side. I'd also shop for a gauge that uses an industry standard O2 sensor so you don't have to pay thru the nose to buy replacements.