[Eleison]

I think the recommendations between XXXholic and Tsubasa are pointless. Saying that they shares the same characters can be true at the beginning, but far deeper into the anime/manga the 2 stories collapse into one big plot.
The Tsubasa movie and the XXXholic movie, xxxHOLiC Shunmuki and Tsubasa Shunraiki, tell essentially the same two storylines from two different perspectives.
We could also add CCS with them, but the connection is not so close like the other ones.
Clamp just play on the dimensional jump, but they all shares the same timeline.

On the other side I could agree on the recommendations with RG veda, because the stories are not directly linked, but they shares only the characters (king Ashura). Here we can speak about alternative worlds.