quick cage/roof rack ?

[XJHOX]

Maybe someone who has done something like this can help me out. I'm going to build a roof rack/tree slider out of 1.5 tubing, I will cut thru the roof and attach it to the interior cage. I was wondering if I can get all the triangulation (is that a word?) from the top rack instead of having to do it all on the inside. Is there any strength differences between the 2? Thanks Jason