Here are a couple of tables I put together to help me zero in on gearing. They work better in Excel where you can filter the columns to show a specific tire size, gear, etc. but I can't attach them that way, so I hope they are helpful as PDFs. I wanted to see what RPM I would be turning at highway speeds as well as what my speed would be at max RPM for each gear.
4L80E_Tables_RPM by Speed OD (55-80).pdf
4L80E_Tables_Speed by RPM and Gear.pdf