The amount that the bottom bracket height will change by half the difference in the tire diameter. The other half is at the top of the wheel, where it doesn't effect the bottom bracket height.

The real number that will effect the pedal strike potential is the bottom bracket height. Bottom bracket "drop" is a frame building spec and it stays constant regardless of tire/wheel size. The distance from the bottom bracket to the ground is the thing that changes with tire/wheel size.

In the case of the Ogre, you would take half the tire diameter(730/2=365) minus the BB drop of 68 and that gives you a bottom bracket height of 297mm. For the 706mm tire that would be 353 minus the 68mm bottom bracket drop for a bottom bracket height of 285mm. You can then subtract the crank arm length(actual length from the spindle to the end of the arm) to get the distance from the crank arm to the ground.