Understanding Society User Support

I am looking only at the Northern Ireland data - I have merged BHPS and US and am concerned with GHQ and self-rated health over the period 2001-latest wave of US (wave 4).
Out of interest I would like to compare GHQ scores in NI with UK and indeed other UK regions. I have read the waves 1-4 user manual and online advice but am still confused as to which weights are most appropriate and the practical use of these.

From what I can discern I am interested in the longitudinal individual main response weight from 2001 to include BHPS, that is n_indin01_lw. Can anyone confirm if this is correct given my research interests?

So for wave 4 I can take this from d_indin01_lw.
Knowing this now, can you point me to instructions on how to apply this weighting in Stata if possible. I am not able to attend any of the training days so will have to work this out myself. I have looped all the variables waves 1-4 US so indin01_lw will be looped for wave b and d - I am guessing I should only apply wave d - how can I do this in stata when they are looped? I know coding concerning pweight and svy but its just isolating the d wave I am unsure about.

Many thanks

Gretta