WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
I built a SE amp using the Shuguang version of the EL156. Connected in ultralinear it was a dandy amplifier with plenty of power. Of course it sounded different than a 300B amplifier - but way different circuit, output transformers and power supplies.
When I put chinese EL156 (KT100 labeled Valve Art) in my amp, I was surprised that they sounded better than my RCA 6550's. No other recent production valve (Russian or Chinese) managed to surpass the RCA's (made by Tung Sol).
Mind you, this was a totally different topology than your question: PP-UL with some local feedback. Timeframe: second halve of the 1990's.