Feeding & Sleeping

I currently bedshare with my almost 4 month old and he is beginning to roll over from his back to his tummy. How do I set up a safe sleeping space for him on our king size bed? My understanding is that bed rails are not considered safe, correct? Or would the recommendation be to set up a side car crib? Thank you!

what are some tips for handling sleep through time zone changes w an 8/9 month old? Specifically opposite time zones, like the US to Europe and back, traveling over a months time Frame. Thanks!

nervous to ask this but here goes: for bedsharing families (we are on a floor bed) what are some indications your child is ready for their own bed? and/or tips for transitioning them without sleep training? not in any rush but wanting to learn