Wikipedia is not a good source for up to date information on the actual alkaloid makeup or content of Phalaris grass species.

3% is really pushing it. I have yet to see anyone reporting even 1% yields with brachystachys, but it might be possible.

My problem with brachystachys, was getting enough for any kind of extraction. It never grew very well where I am and I abandoned it for aquatica, which has given me enough plant material to extract and active yields of mixed tryptamines.

The reality is that, the data you are looking for, is more or less non-existent.

Be a pioneer.