The small mount goes on the driver side and the big one on the pass side. In my 5 there are only 4 holes on the frame so not sure which you should use.
Not sure about the bracket.
From what I've read, the D44 disk brake upgrade uses the same parts (96-01 maxima or 300zx rear calipers, hangers and rubber lines and thin tracker brake rotors). The only change is the custom bracket that mounts the caliper to the flange
Sell me your Scout II Dana 300!!!
I'd prefer one with a manual bull gear, but I'd consider buying one with an automatic bull gear for the right price.