Someone else will chime in I'm sure, but in general the '59 neck is similar to the '58, maybe a little slimmer. The slim taper necks are supposed to be on the '60 models. (They always vary a bit, but not tried any very recent models.)
My 2001 '59 reissue is comfy, but still on the chunky side compared to my 1990 standard (which has a lovely slim taper) or my LP Special RI (non historic).
I you want a slim neck you really need to find a '60 reissue to try before you make any decisions. Definitely can't say the '59 is the "best", and they certainly shouldn't have the slimmest necks. There's a GORGEOUS (2005?) '60 reissue in the "what LP have you got" poll, which might whet your appetite...
What Historic LP do you Own ?? Historic Headcount !!