Several years ago Consumer Reports did a study on tire gauges. At the time digital ones were just coming on the scene. They gathered up hundreds of different gauges and several samples of each. What they found, was, that the simple stick type gauge was extremely accurate, no matter how cheap or who made it, and that digital ones of that time were for the most part, also just as accurate, but not worth the extra money.
A couple of gauges were eliminated due to defects in the design of the head, but all in all, they all tested accurate within I think it was a pound, and it came down to the design and angle of the "foot", straight, angled, double. and whether it had a depressor to release pressure.
I have removed the wheel simulators from my Sprinter, and I have found that a tire gauge with a long stem and a foot that has a straight end and a angled back fitting work perfectly. I also got a long Milton service end to use that is designed the same way.
https://www.amazon.com/gp/product/B004QI1WEA/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
This is an interesting one, very similar to mine.
https://www.amazon.com/TireMinder-Precision-Replaceable-Batteries-Warranty/dp/B01301305W/ref=sr_1_75?s=automotive&ie=UTF8&qid=1469026675&sr=1-75&keywords=digital+tire+gaugeSame/similar but cheaper
https://www.amazon.com/TireMinder-TMG-DUAL-2-Digital-Pressure-Attachments/dp/B00C5THRBO/ref=sr_1_101?s=automotive&ie=UTF8&qid=1469026756&sr=1-101&keywords=digital+tire+gaugeThis is the gauge I have. Paid about $10 at Ollies for it, Slime has discontinued it. It does work well.
https://www.amazon.com/Slime-20165-Digital-Truck-Gauge/dp/B007OXC97S/ref=sr_1_141?s=automotive&ie=UTF8&qid=1469026837&sr=1-141&keywords=digital+tire+gauge
Charles