The logistics sound pretty frustrating and out of your control for now.
I've read your sitch from the beginning and know about xh and from what you've stated of past history I imagine that SD & SS will be w/ mom almost full time in the near future.
Perhaps then you will be able to spend more time with them.
I hate it when I don't see my kids for a day or two at a time and empathize with you, it SUC*S!!
