billet wheel 480 with a 1.15 housing.
youre way over thinking this. you are very fuel limited and at this point, rpm limited (you give no hints at building something that will see rpm or beyond stock engine at this point). the split you are thinking about isnt something you are going to feel/see. your small turbo has a greater affect on this. the 1.32 would work just fine as well, ive driven both but for what you have, the 1.15 is better suited though.
youre way over thinking this. you are very fuel limited and at this point, rpm limited (you give no hints at building something that will see rpm or beyond stock engine at this point). the split you are thinking about isnt something you are going to feel/see. your small turbo has a greater affect on this. the 1.32 would work just fine as well, ive driven both but for what you have, the 1.15 is better suited though.