You should be ok with 40w total. If you want to play it safe consider an LED headlight.

Thank you Gary and Dave.
Makes sense to swap everything out for LED while I'm at it.
Do you know of a source for replacements... before I go surfing.

I have had very good luck with the Lasfit bulbs.  They are reasonably priced, and their customer service is very good.

The middle priced model is likely the most bang for the buck, and easier to get into the headlight bucket than the expensive model that has an external driver.

https://www.lasfit.com/collections/h4

The ones I linked are PnP.

FWIW, the whole 'can the system support this accessory' question is a classic case of reality vs theory. I'm on a few old bike sites and this question comes up all the time.
The engineer types and those who love memorizing statistics always pull out their calculators and make statements yea or nay based on theory.
My experience is that older bikes often have a significant deterioration in the charging department. Sometimes it's because the permanent magnets in the alternators lose their strength (vertical twin Hondas). Sometimes regulator rectifiers lose their efficiency. Most often, the cause is lots of corroded connections and not-so-great grounds.
SO
If you want to know if your system can handle your new coffee maker or whatever...
Buy a good digital voltmeter. Charge up the battery for a day. Put the meter on DC volts and connect across the battery terminals. Start the bike and observe the voltage drop while cranking. If it drops below 10V in decent weather, something is not great.
Then, ride the bike for a few minutes to bring back the electrons lost during starting.
Observe the voltage at idle. Make note.
Slowly rev up the bike til the voltage stops climbing. Make note of RPMs and voltage.
Compare these numbers to the factory shop manual.
Suzukis were a bit looney on peak voltage. Don't be surprised if you see 15.5V peak.
Now, connect your accessory and test again.
If it's an expensive accessory and you haven't bought it yet, and won't if it won't work, pick up a light bulb with the same wattage draw. A simple sealed beam draws 55-60W and is pretty cheap. Lower draw accessory? Get a smaller bulb.
Connect the bulb in the system wherever you'd attach the accessory.
Rev the bike up and see at what RPM it breaks even.
If this is above your normal cruising RPM, all is good.
If it isn't, then you can start making things better. Starting at the battery, disconnect the electrical connectors and clean them. There are all sorts of goop you can put on connectors to keep them from becoming corroded.
Where the ground go to the frame, probably the paint was removed by the factory and there is rust there. Clean it off.
It also doesn't hurt to upsize the charging system wiring. Heavy amperage cables from the battery to the solenoid and to ground.
I've often picked up more than 1/2volt in the charging system just by cleaning things up. And even more when I went to new cables.