Rich:
For me it's the painting that makes me nervous. Truth be known, I worked for three years behind a seafood counter at a huge supermarket, I once helped fillet a 150 pound Alaskan halibut (probably the last one), imagine, pure white halibut almost 4 inches thick, deep fried, with chips, okay, I'm way off topic, but sawing and cutting seems so much easier because of the repair stuff around. But man, mess up a paint job?
Yeah, you can always fill and sand, and the Mr. Tarmac really helps get you to a great surface. Like you Rich my brush hand isn't what it might have been, but like you said, those intakes will look great. Remember to leave lots of tolerance in your cuts, no point cutting too much off the first time and back filling. I like to leave a generous amount behind, up to a 1/16th if it's critical, and then gently use a scalpel or Xacto to shave the shape, then xtra fine files or rifflers to get the final dry fit. Yeah, lots of dry fitting and pencil marks in between making the surgical adjustments work for me. You may only need CA or gap-filling CA, patience and time willing.
Oh yeah, don't for get your xtra-fine razor saw - and lots of tolerance.
As for patience, I'm staring to think it is just having a positive attitude about procrastination!