8 point roll bar
So I went with the one and a half by two and a half so I could slip it inside the rear subframe like this picture I got off the internet kind of, but again like you did without having to go through the rear floor board. The picture that I'll post here is I don't think a duster but it's the general idea of what I was thinking since my rear frame rails are 3 inches wide I figured the two and a half inch would slip right inside of it and then I can well weld the little area on the bottom also.
View attachment quickndirtysubframeconnectors02.jpg