I've seen push/pull 300B amps with as much as 28 watts. But push/pull can never sound the same a SET due to the topology difference which results in different wave forms from the two different formats. Single ended amps are asymmetrical amplifiers in the sense that if you imagine a simple sine wave signal the single ended amp produces different wave forms for the top and bottom wave portions. The bottom half of the wave doesn't go as low as the top half goes up. This is inherent in SET topology for any parts. Push/pull is symmetrical. The very high second harmonic distortion that makes SET amps so nice is a result of this anomaly.
But all audio electronics are different compromises. You need to learn which compromises are the ones you need to hear.