As far as I know, concerning the sound, the reed strength should really make no difference (I am summing up my physics knowledge, and the sound is in fact more in the reed cut/form than its strength).
The Reed strength is just a compensation for the human organism (diafragma strength, lung volume, lip strength and gut).
So there is no need train for higher reed stregths, in fact I believe everybody is different and for some people a lower number may be the natural limit, but this should in no way affect the sound produced…
Hey everyone! I have some advice on growling. I’ve only had a saxophone for I think 3 weeks and I am able to growl! I will tell you how I do it. I make a gargling sound into my mouthpiece! I gargle without mouthwash of course, but I just gargle, kind of like purring like a cat. It works for me, and I hope this helps others.