Hi @tennisitis, IMO pre-stretching Black Out 1.24 destroys the redeeming features of the string. Last thing I want to do is to remove the elasticity and in my experience that is exactly what pre-stretching any typical poly string does just that. It changes the nature of the string usually for the worse.I'd appreciate it if anyone can share additional experience regarding poly prestretching.
Give it a try, but if you are getting a stringing machine I think you will find that nothing beats a fresh bed of Black Out. Whether you are prepared to re-string every 4 or so hours of use is up to you. If you like the combo, perhaps purchase another racquet so that you can reduce your re-string frequency.