As to the culture, I'm pretty good at it.
Is it found in nature submersed? I've seen several acres myself.
You also pointed out that Amano seems to do fine with it.
I have a turf in two tanks. I've grown it for about 8 years or so? Something like that. Main thing is keeping it nice a clean, don't let things settle in it, sinking Riccia will intermingle, bladderwort, algae can get tangled in it. Other than that, it's pretty easy to deal with and requires no pruning to speak of.
I hear folks whine about trimming their tanks etc, and how hard Amano's tanks are etc, well Amano likes these tanks for reason. They are easy once established. Crank the CO2 up high, add lots of shrimps and take care of the NPK and traces. No pruning like stem plants. You can check the APD also.
FYI, you might hit a nerve bringing that name up with a number of people. They are suing a number of customers that complained about their service.
Regards,
Tom Barr