Howse 600S 6'Rotary Cutter?

[PSDStu]

I got my hands on an old used and abused 600S rotary cutter and need to replace the PTO shaft, and gear box.

I called Howse and got them to fax me the parts list and it includes 5 different possible PTO shafts:

Part Number Description
14H-30QDSP DS COMP 30" 1 1/8 SQ T-13" B-15"
35RN-40QDSP DS COMP 40" 1 3/16 T-20" B-20"
35RN-46QDSP DS COMP 46" 1 3/16 T 26" B-25"
35RN-40QDTL DS COMP 40" 1 3/16 T-20" B-20"
35RN-46QDTL DS COMP 46" 1 3/16 T-26" B-25"

I was wondering if anyone has any idea what Part Number or Description information may mean?

I am thinking that "DS COMP" is compressed distance between the center of the u-joints, but have no idea what the "T" or "B" measurement means?

Stu