Global Mapper v24.1

Which Datum to use for British Grid

Blooper Global Mapper User
Could someone advise me on the best settings for working with British OS vector drawings please? I usually work in Northern Ireland and just wanted to be sure I'm setting things up correctly. I know I need British Grid projection and OSGB36 datum but there are 3 OSGB36 options as below OSGB36 (7-PARAM TRANSFORM) OSGB36 (BEST TRANSFORM) - NTv2 Grid OSGB36 (NTv2 Grid) - NTv2 Grid Would appreciate if someone could confirm which is best for me. Thanks.