How would you fix this cowl rust?

That's far too hokey for me. Right now here are the approaches I am considering:

1. Snake my hand up there with a die grinder and remove the old rust, do my best to weld in a patch and seam seal the crap out of it.

2. Use fiberglass filler or Metal 2 Metal after grinding away all the old rusty metal.

3. panel adhesive a patch in??

If all of that fails I will have to cut the cowl apart. I do plan to paint the car, I was just hoping to put it off for a little while longer.