A fair point with regard to the 300b SET amplifier . I will add however that all 300b SET aren’t created equally for sure. Where some will run out of steam, others continue to cruise along. Three key design factors.
1 Robustness of the power supply.
2 Quality of the output transformer
3 Driver tube selection and implementation of this section.
Agree with you that if a 300b SET just isn’t suitable for the particular circumstances/speakers,the 805 SET is a terrific alternative suggestion.
Charles