An alleged schematic revealed by Engadget Japan alludes to the iPhone 6S as being slightly thicker than the iPhone 6. If true, the 6S will be 7.1 mm thick, a very slight increase over the existing iPhone 6’s 6.9 mm profile. The increase in size could be explained by rumors that Force Touch will be making its iPhone debut in the new model. Sources have claimed that any change to the 6S won’t be big enough to alter how existing iPhone 6…