Nice job 2l2q! It's hard to see in your installed pic, but it looks pretty flush. Is it? Those other 5g tracks and slider parts might come in handy. Mine was just a little bit above the roof, but it bothered me knowing it was like that - plus it chattered a little bit on the freeway sometimes when it was closed - so the other day I wrenched out the 4g slider arms and put the 5g ones in, along with the 5g brackets (no drilling required for those!). That made it perfectly flush in back but point way up in front. :P So I put the front of the brackets in a vise and bent them down and then flat again to try and lower the mounting position. Now it only points up in front a little, although still too much for my taste. And now it rattles a little when it's open, but at least it's silent and snug when it's closed.
Let me know how it goes.

Dan