This may seem like really stupid advice, but for whatever it's worth...
Why not get him a bottle of the one that you know he likes?
If I were in his place, I would consider it a very thoughtful gift. I would much rather receive one my favorite malts than one I might or might not like as well, and that if I did, might or might not be readily and inexpensively available as a repeat purchase.
So many malts, so little time...