Tire sizing from mm-in

[JeepinDoug]

I'm shopping for a set of tires and trying to figure the measurements in a language I understand. Let me start with the factory tires on my truck.
To be practical I'm using numbers only;
265/70/17
265 is the width of the tread in millimeters.
70 is the percentage of the tread that measures the sidewall per side.
17 is the rim diameter in inches.
To convert into inches we'll start with the 265mm
1 millimeter is approx .0394 of an inch.
.0394 x 265 = 10.441
This number gives us the width of the tread, approx 10-1/2" wide.
The sidewall, per side, would be 70% of the tread width.
10.441 x .7 = 7.3087
7.3087" is the measurement of one sidewall.
To find the actual tire diameter we add two sidewalls and the rim diameter;
7.3087 + 7.3087 + 17 = 31.6174"
So my stock tire, (265/70/17) measures 31.6174" tall.

I'm shopping for a tire that measures around 33" tall using the same rim. If my calculations are correct a tire with the metric notation 295/70/17 will put my tire at 33.2722" tall.
These calculations are never perfect with the other variables thrown in, tire pressure, rim width and weight of vehicle but it's a good ballpark figure.
Do my calcs seem close or am I'm missing something?

I'm also looking at the NittoGrappler LT295/70R17D1 121R B. Anyone know the load rating on this tire? Is it D or B?
I'd love to get the Bridgestone Revos but I can't wait for a taller tire, plus I think the load rating is really low, having a hard time finding the correct info.