https://3ds.guide/dsiware-list
They are sorted by price.
Apparently Legends of Exidia is the only one I see with a DSiWare inject file however ATM for EU.
I'm not really sure about the second part. I don't know why the system transfer is even necessary then if I can legitimately purchase the title via ctr-httpwn on the target anyway. Maybe you can't inject the DSiWare file into a .cia. I kinda want to finish this process before I get too sure of myself even though the hax does load correctly, but it seems that purchasing the title on both systems works.