A question of size
The 80" Midwest series is an excellent choice. My first competitive IMAC bird was a Midwest Cap 232 with a Moki 2.1. If I would have known what I know now about gas engines I would have used a different engine.
You will be able to feel differences each time you jump in scale.
"Giant Scale" as a standards term is usually associated with being "IMAA" legal which I believe is 80" for a monoplane. (someone correct me here If I'm wrong) but in other circles seems to be centered around the 40% birds.
The amount of "Technique" and setup you have to learn depends on how competitive you want to be.
It's been a while so I'm not sure on the price points.
I personally wouldn't go redundant on battery, but I would definitely use good servos and use a separate servo on each surface.
Sure.....You should be fine at fields with moderate size runways.
(250-350ft)
Bill Higgins
San Antonio, TX