'10 C'Dale Tandem RT2. '07 Trek Tandem T2000, '10 Epic Marathon MTB, '12 Rocky Mountain Element 950 MTB, '95 C'dale R900, "04 Giant DS 2 '07 Kona Jake the Snake, '95 Nishiki Backroads
While I would not consider most tire guages as precision insturments, my expeience has been that most are pretty accurate to within a couple of pounds. To do a rough check on yours cross check it with a friends or at the LBS.
Tires rated to 110 will ride at much lower pressures without immediately noticable differences in handling. I always find mine to be more predictable at the max pressure. I only have analog gauges, so I'm of no help there.
Yeah the tyre rides fine when I'm in the saddle but when I'm out of the saddle going up a hill the front tyre moves a little from side to side so that can't be good, will have to invest in a good floor pump by the look of it.