Understanding Society User Support

I'm using all 9 waves of data and need to choose the correct weight.
I understand that using 'indscui_lw' appears to be the correct choice, considering that I need longitudinal weights, I'm using the self-completion data and I'm using data up to wave 9. However, I'm still unsure on a few things:

1. For individuals who are present in all 9 waves, do I then need to copy the weight from wave 9 into every other wave for each individual?
2. Suppose an individual is present in waves 1-8 but not in wave 9, do I then use the value of indscui_lw from wave 8 and then copy this to waves 1-7 for each individual?
3. Values of indscui_lw are only available in waves 7-9. Suppose I have an individual who is only present in the data from waves 1-6. As I do not have an indscui_lw value for them, do I then take the weight from the equivalent measure, indscub_lw, which is available from waves 3-9? In this case, should I then use indscub_lw for everyone?

Thanks in advance.