Hello, as far as i understand krpano it's not the final tiles size that will set the quality of you jpeg. You should have a look at the "templates" folder which is used to set parameters in the vtour or multires creation. There you will see that the multires conf file calls the "basicsettings" in which I can read :
Code
# image filtering and compression settings
filter=LANCZOS
jpegquality=82
jpegsubsamp=422
jpegoptimize=true
Then you can test which settings gives you the best quality you want without taking too much time for loading.