Wait, you’re looking for dual drive at just 800€? You definitely should have just ponied up a bit more cash for that Haya build. At 800€ I’d prefer a well built single drive than any dual drive if I were you.
If you built the board yourself, you could maybe get a good dual drive by finding good deals on all the parts / buying in bulk from a vendor, but even used builds go for a bit more when they’re dual drive…