Understanding Society User Support

Hello! I am using data from the USoc to evaluate the impact of childcare on children's outcomes. In looking at the data and the weights, I have the following questions I was hoping to get some clarity on:

1. Is it okay to use different weights across different datafiles which will be appended (long format) and which information across datafiles will be used in the same analyses? For instance, the weights in datafiles child and indresp are different (e.g. indresp weights include indpxus_lw while child weights include psnenus_lw).

2. Why do some weights disappear after certain waves? For example, psnenub_xw disappears in wave 9 in the child datafile, but psnenui_xw appears - is it okay to use these different weights across waves? Equally if I am using the data longitudinally and cross-sectionally?

3. The USoc guidance says to use longitudinal weights if using more than one wave, and cross-sectional weights if using a single wave. If I want to use more than one wave but analyse them cross-sectionally, should I still use the longitudinal weights?

Thank you very much.

Best,
Julia