DR DDT's. I use these on a couple basses and they work quite well. I was a DR Lo Rider guy before that (and still am to a degree) and the DDT's just give you a little bit nicer tension when tuning down.
Circle K's. Seriously - these aren't any more expensive than buying strings off the shelf, and you can get fully customized sets for whatever tension your comfortable playing at. If you have questions, email Skip (owner) and he'll get you setup perfectly. I went this route for my current projects tuning - A#C#G#C# - and his strings were a lifesaver!
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