This is not a detailed explanation but your plans are all wrong in my opinion. What you would do is simply thin this glass down by "grinding" it ,though I wouldn't use a "grinder" I would be using an 8" Orbital sander, much more user friendly.
Anyway, so you thin the glass down to just about nothing. Then you brush it with resin and then lay pieces of resin soaked mat over the area. Sand that just like you would a body filler, shaping it to match the hood. Finish it off with "Fibertech" from Evercoat and there you have it. Once you get the top into shape you turn the hood over and do the same thing on the underside.
Splicing in a section is very difficult in that you are VERY likely to end up with a problem with "ghost lines" after the whole thing is done.
Remember that this hood isn't "fiberglass" but "SMC" and you need special resins and filler (The Fibertech) when working with it.