Can you show me where you are getting the current specs for the heated devices? A pic or point to the URL. The ratings sound not only high but are vague. Knowing what the peak current draw is and what it drops down to after the elements heat up is more important.
Most heated clothing devices are known as wire wound. Their current draw is very high at first but as temp rises, their current flow drops which is a good way to self regulate what they heat to.
All I can find on the 08 charging system is that it is 3 phase which is what is necessary for low ripple. Some Jap auto makers use 4 phases for a very clean, low ripple output for onboard electronics. From an earlier comment it sounds like a delta wound stator since the rise in RPM increases output. Delta wound stator charging systems are by nature higher output then (Y) wound which put out near peak current just off of idle. Delta wound stators have to be wound up a bit to hit peak output.
It wouldn't take me long to test peak output, I have the test equipment to do so. What that doesn't tell me though is the quality of regulation and how long it can be full fielded. Low RPM's with high current load will be the least of your problems.... that only results in a discharged battery. High current load with high rpm's and a regulation system not designed to protect against a high duty cycle will result in a cooked stator.
What I am finding as I talk to my dealer and look over the service manual is Suzuki keeps even their technicians in the dark. I don't see how that benefits anyone.