UBI sees everyone receive an income, typically with a clawback mechanism. GBI sees an income paid to only those who need the support (means-based). The difference is subtle, I suppose, but could have a dramatic effect on what the studies show — or maybe not, I don't know. The key takeaway here is that I've never been able to find a UBI study to contrast the numerous GBI studies I am familiar with against. You spoke of UBI studies so I was hoping you'd be able to share. But, it seems not.

I don't understand the questions you are asking at the end. Apologies for not having a good answer.