You asked the question what wattage can I get away with without damaging the bikes electrical system. As you are probably aware LED lights are very low wattage so I gave you a 'bog standard' answer to basically cover the question and to 'put your mind at rest'. If I had known that you wanted more detail I would have offered it.
When I said 'nothing that you put on your bike will damage the electrical system' I was correct.
All stators as standard have a 10 - 15% reserve to handle accessories. They are designed to produce more than enough power to operate all of the vehicles possible 'electrical draws' from a low rpm.
If your stator is working correctly and with every electrical item turned on you will never draw the normal operating capacity of the stator. You still then have the 10 - 15% reserve at all rpm's as well.
Even if you added something that did draw the full power of the stator there would be no damage to the bikes electrical system - the lights would simply be dim and some equipment may not operate correctly. If allowed to continue the battery would go beyond a usable voltage.
The only way you will damage the vehicles electrical system would be by fitting a stator that generates too much power or by altering the voltage regulator.
I doubt you will find anywhere the actual output of the stator but a simple way to test this would be to put a multimeter on the leads and check the output.
The advice I gave was based on the fact that the stator will easily carry additional voltage for LED running lights.
As to Harley's starting their lives damaged? Well, Harley and most other motorcycle manufacturers now have an additional connection from the fuse box for 'accessories', this can be from 5 to 15amp (sometimes higher) in order that additional lights etc. can be added.
You can calculate the wattage / amps here on this link if you are uncertain of the wattage you can use up to: https://www.electricalsafetyfirst.org.uk/amps-to-watts-calculator/
Not sure if you have the GW250 manual, if not it can be downloaded from the web:https://www.manualslib.com/manual/815691/Suzuki-Gw250.html?page=10#manual