How to collaborate across time zones

• Change your settings in Google Drive and allow anyone in your organization to edit new files. Then someone can make a change before they lose their train of thought. You can always revert the changes you don't like.
• Always include links.
• If you use a group chat tool, communicate in public channels unless it's a personal or sensitive issue. A public database of chats allows teammates to find answers to their own questions.
• If you have a video call, record and share it with others that weren't able to attend due to time zone issues.

Small talk allows people to stay in the loop with work projects. Posting updates about what you're working on allows for better alignment with the rest of your team. 

It will enable others to review any conversations they may have missed and contribute to in their own time. Be sure to have a system for it, like an internal blog.

If you are in Denver and the person you're asking is in Perth, waiting for approval or 100 percent certainty will slow every decision down by one day.

As long as there's no irreversible risk, act first. You can always adjust later.