+ what spec said...
You cannot run a Gerbing jacket and 30 watt draw grip heaters or gloves on a standard +08 KLR with low & high beam on.(The Gerbing vest draws about 50 watts, so it may be a better choice for power conservation on a KLR)
I would suggest you add a LPC-x-W2 License Plate Light, LED type from Super Bright LEDs, Inc. ( superbrightleds.com) the cost is $5.95. This light draws 50 mA, or 5/8 Watt at 12.5 Vdc. The standard Lic. lite on the KLR is 4.5 Watts. By the way, this lite will fit the stock KLR lic. bracket after removing the lens and R5W socket assembly, you can splice in the LED light, the bolt pattern is the same as stock. Be sure to observe polarity, after all, these are LED's. The old bulb center contact is positive and it's wire connects to the red on the new LED light.
The way the power controller for heated products work is by cycling on and off the heating circuit. Either it is full on drawing (75 W + 30 W) / 12.5 V = 8.4 A current, or 0 A current. For standard filament or halogen bulbs, they will see a voltage reduction at their terminals due to the voltage drop caused by the wiring resistance. You see that as a pulsing when the control is switching on and off. (when the control is fully on, no cycling, you should not see any pulsing....)
HID lights with their internal power supply will keep the brightness constant at the lights, even when the supply voltage input changes (the input current goes up when the supply voltage decreases, no free lunch here.) If you do use HID or want to use the high brightness Sylvania bulbs, to get the best results you must wire from the battery a 12 gauge hot and ground direct to the lights via two control relays, one for high, one for low beam. The KLR wiring and handle bar switches are fine for the masses, but drop too much voltage for the aficionado.
Keep in mind that at colder temps, the internal resistance of the battery increases, and any current drawn will cause more voltage drop than a hot summers day. (the ability of the battery to store charge is reduced...)
The total power output of the KLR +08 models is about 220 W, but this power is available only at high RPM's (I don't know the exact specifics, but I would assume from the manual test conditions it is 4,000 or more RPM)
Under 4000 RPM, the power available decreases.
One strategy you may consider, for daytime riding, is to install a switch to turn off your low beam, and turn on a 10 W LED spotlight for daytime running. Then it is possible to be safe, run you Gerbing jacket and heated grips at full power all day.
One last point.. if you do have a cycling type heater control ( a must have item on the KLR in my opinion), this will play hob with any type of current or watt meter, or any voltage meter. In this case, your only option is to either turn the heaters fully off and take a reading, or turn them fully on (no cycling) and take a reading.....