Cadence is a fun statistic to geek out on but it is not necessarily an indicator of a 'right' or 'wrong' way to pedal your bike - If you're not in shape for it 95 rpm is going to be uncomfortable (and unsustainable) no matter what your gearing is.
Without a computer to look at, just ride by feel - a steady and even turnover rate that you are comfortable with. Use your gears to achieve the resistance and moving speed that you want (Somebody said before that your gears are there to serve you - that is true). Your actual rate is just a number really and like millions of riders before you, you can get by without knowing what it is.
One other thing to consider (not sure if this even applies to you) is one's form - Us big guys tend to start out riding with our knees sticking out. If you really try to work up to 90-95 rpm, that is an uncomfortable arrangement. Work on keeping your knees in so that your thighs are more or less parallel to your top tube. It's a lot easier to spin that way and it's got to be better on one's knees. That might be the only useful thing I have ever taken away from watching the TdF.