I've notice while backing up my games that there was a download size with was around 40MB and a file size thats 200 something MB. If I use an r4 or similar will the rom take up 200 something mb on the microsd or will it take up 40mb?
Throw it on the card and take a look. 40 megs for an .nds file doesn't seem out of normal, I don't think. 20- 25 nds files on a 1 gig card sounds about right.