I replaced the outer cowl, inner to outer piece, and the inner kick panels when I did my truck over. This was before the newer redesigned lower cowls available now, and the replacement lower cowls stopped well below the hood curve. Now they include the hood curve which is often gone from rust through and I recently learned is what GM put out. I saw an original NOS lower cowl replacement piece for sale on eBay and that's the first time I noticed it. Long story short: The fit was lousy then and it sounds like things haven't changed.
I'm afraid that it's the lay of the land. That's why they make big hammers I guess.
The good news is that you don't have to fabricate everything you need. The bad news is you might spend as much time fitting as you would have fabricating anyway!
