Do a dry run installation first. The (rotation-wise) gap should be from the tips of your fingers to the heel of your palm.
If they are like EE grip warmers, toss the resistor. It is normally employed to draw off excess capacity to balance the left and right sides if you do not insulate as follows:
Use friction tape or a shrink tube on the clutch side under the heaters so as to not lose heat which would to the handle bar. If the throttle tube is aluminum, insulate in the same manner. Insulation conserves and puts to use the otherwise wasted capacity.
Most bikes do not have the capacity to run both these and other high-draw electrical components, like lights. If you need to run them all, get a lighting-coil rewind to increase the supply.