I think that you are fine with a any standard / generally accepted .38 or .38+P load. Speer Gold Dot, or the like in 125-158 gr. No need to use anything weird.

I fired off a .38 Spl from a snub, 125 gr. Federal Nyclad, in a walk-in closet one time. The previous post about "Eeeeeeee Street Band" is right on the money. It was sort of disorienting and both ears going "eeeeeeeeeeee" for hours. Felt it in my left ear for days. All good now.