Welcome to MobileRead, tm3
Two K3's are the way to go, for sure. Make sure they are both bought on the same account, with the same charge card, then you can both "share" books.
The best way to see if you like new authors, is just to look at the synopsis, and then take the plunge if it interests you.
If you try a new author from Amazon, you can download a sample to see if you like it.
This board has lots of indie authors that I would have never known about......and I've found some wonderful reads.
All genres are represented. The neat thing? Their books are very inexpensive.......
AND......don't forget the free books available here...public domain, beautifully formatted for whichever device you decide on.