I have a narrow-phyllode acuminata plant. However, it is very slow and kind of ugly - I much prefer courtii aesthetically. Frankly, that is more important to me at this juncture than alkaloid content. I like knowing the alkaloid is there so I have an affinity with its 'spirit' or whatever, but I use this molecule so rarely that that's a secondary concern.
I was not aware that courtii was such finnicky one - perhaps that contributes to its rarity. Is it much worse than M. hostilis or A. acuminata? I live in a temperate area and have to bring my mimosa indoors for the winter, and it promptly drops all its leaves and barely pulls through. My acuminata is over a year old and looks like a month-old weed still - in summer sun or under an LED light, the damn thing takes forever.