Audio Programming using SDL2 - Setting Up Audio Device

I'm writing an old-school game engine in C and SDL2. I'm designing the audio portion now. Instead of playing .wav samples and the like for sound, I want to implement a sound generator, kind of like a SID chip in software (if you're familiar with the Commodore 64).

Here is my initialization code for setting up the sound device:

void initialize_audio(void) {

    SDL_AudioSpec want, have;

    SDL_memset(&want, 0, sizeof(want)); //initializes the 'want' struct
    want.freq = 44100;
    want.format = AUDIO_U8;  // 8-bit sound
    want.channels = 1; // 1 = mono, 2 = stereo
    want.samples = 2048; // how to decide on this? must be power of 2
    want.callback = my_callback_function; 
    
    // capture global audio_device_id here
    audio_device_id = SDL_OpenAudioDevice(
            NULL, // choose best device based on 'want' struct
            0, // want a playback device, not a recording device
            &want, 
            &have, 
            SDL_AUDIO_ALLOW_FORMAT_CHANGE);
}

My question is (or what I need help with): I'm not sure what to ask for in terms of the buffer size in the audio device (the 'samples' parameter). I know this will effect how often SDL calls my callback function to feed more audio data into the sound device's buffer.

My guess is to keep it as small as a number as I can afford to do. The smaller the number here, the more frequently the callback function gets called, but I'm not sure what benefit this would give me.