Old 38 S&W top break loads?
You said 38 snub nose 200 grain. The larger 38 "special" was tried with 200 grain bullets long ago according to some article in one of the gun magazines about 45 years ago.
The British championed it because they were looking for a smaller frame gun after WWII, to replace the 455 Webley. Allegedly tests by them showed that "knock down power" was more dependent on the time the bullet spent traveling through the body. Slow bullets were claimed to be superior, according to them. (Wrong)
The velocity was so low it would not break a car windshield so police in this country gave up on it quick. All our tests (before hollow point bullets) showed the 38 special penetrated best with 158 grain bullets (if memory serves - someone will hopefully jump in on this).
Anyway you might want to read about the old 36 cal black powder revolvers (remember a 38 special is really .357 or 36 cal). I sorta think the old original 36 black powder revolvers were okay but 44 much better. I vaguely sorta remember the 36 doing 750 feet per second out of a 6 inch barrel (some black powder person here will correct me). They shot both round ball and bullet shaped mini balls before cartridges. I will make a wild guess and assume a round lead ball of 36 caliber would be about 80 grains?
I am taking the long way around in trying to say you are covering old ground. Lighter faster bullets do best within reasonable limits. You are talking about something that will shoot worse than a .32. A friend of a friend was shot by a 32 once and it did not penetrate his sternum. It knocked him out but did no real damage.
You might want to read about the old 38 long colt, the 38 smith & Wesson that you have, and the 38 special that was more competitive for police markets. The 45 dominated the military market for a very long time (late 1800's perhaps). Some nice 45 single then double action revolvers were sent to the Philippines during the insurrection. They solved the problems of the old 38 long colts poor stopping power.
Try the factory load first. There were a lot of good reasons for the original load. If you want to shoot a 200 grain bullet at low pressure buy a 44 special or 45 auto or long colt.
My Speer reloading manual number 12 (1994) warns against using any of its 38 S&W loads in a pre WWII hinged pistol (top break) unless it is a Webley. It has a few nice loads listed for 110 grain bullets for new revolvers. Fair loads for 148 and 158 for new revolvers.
It is fun to play with old revolvers, but not worth blowing up an old weak top latch into your face.
The National Firearms Museum: Smith & Wesson 38 Double Action Perfected Model Revolver
That is a nice looking gun made between 1908 and 1920. Please do not blow it up.