I wish I could help but I am not familiar with Spektrum radios. Are you saying you cannot load files onto the sd cards?

Typically you can just download straight to sd card. The NX radios take .nx files and so can the IX radios

Not too much different to be honest. Don’t think about it and you most likely won’t notice a difference. Inverted is easier and low wings can stall slightly easier especially with edfs, but as it’s a trainer it won’t have that bad stalling quality.

My experience graduating from a carbon cub to a commander went well for the most part. Biggest difference I noticed was landing takes a lot more finesse having to learn throttle control before touchdown and you can't just glide them in like a high wing. Also it reacts much quicker. Like the above...