Help me I'm stuck regarding RMF and Motors

[abexomotron]

Hi All,

Firstly I'm new to this robot stuff. My school gave me a task to design (not actually making it , just design) a robot that can inspect oil crude tank. The most important task is to move the robot from top to bottom of the tank (all methods can except manually using cable) and be able to move the robot around the bottom of the tank for inspection ( with oil and sludge).

After reading tons of research paper on the net, I really like the concept of magnetic wheels.

Here's a not finish sketch http://img20.imageshack.us/img20/1482/robot1ib.jpg

I will use Torxis Heavy duty servo motor for each of the red circle wheels
The middle wheels is connected by shaft and geared with spur gear (Green 1 and 2) and using another motor (purple).

What I'm concern about is 90 degree climbing and moving around the bottom with sludge. I use the RMF calculator for the 4 servo motors on each red circle wheels for 90 degree incline (without taking the Force of magnetic on the wheels and the middle wheels).

Here's the RMF results:


So I need to choose a gear set and a motor so that the middle wheels will have the same speed as the 4 wheels but larger torque to be able to climb 90 degrees (with hydrostatic force of oil and body weight) and assuming that Fmagnetic=170N for each wheels. correct?

Please comment about it. I'm actually kind of lost now.

[abexomotron]

And also from the RMF results data: "Motor Rotation Speed" is the wheel rotation per (second or minute) right?