Had a brief chat with Shaun from Fused Flora.
He's tried around 30 different batches/suppliers. He said Hirsuta has a low ceiling and is very hard to get dialed in. It’s also very course so you should use a scale. Hard to say what amount is best for you, but he takes 3.5 grams, gets wobbles at 3.8 grams, and no effects at 3 grams. It’s a very small window.
Thanks for posting about this. I’ve been seeing more and more people talking about hirsuta recently, many complaining about issues after taking too much. Hopefully this helps others avoid what you went through.
And please get a scale, there’s really no way of knowing how much you’re taking without one. Even plain kratom powder varies in density, especially with the new nano grinds becoming popular. Amazon has a bunch around $10.