From Google, there are dozens of nozzle and flange manufactorer catalog sketches, images, and diagrams.
Do not use your awkward Long Weld Neck Raised Face "abbreviation" just type the full words under google image search.
ASME Section VIII Division 1 clause UCS-66(c)(4) defines a long weld neck as :
Long weld neck flanges are defined as forged nozzles that meet the dimensional requirements of a flanged fitting given in ASME B16.5 but having a straight hub/neck. The neck inside diameter shall not be less than the nominal size of the flange and the outside diameter of the neck and any nozzle reinforcement shall not exceed the diameter of the hub as specified in ASME B16.5.
You may find many vendor's catalog on-line for the long weld neck flange detail.
Basically, the required thickness of the straight pipe section is specified by the Engineer based on the design requirements. And, the type and dimension of the mating flange is based on the B16.5.