Managing Sierra to High Sierra upgrade

[Al_from_Ottawa]

Thanks for your usual quick response.

1. The initial migration: Glad that my plan sounds feasible. I assume that by specifying shared users I will get all users of the MacBook transferred.

2. If I end up on High Sierra, I will want to migrate to APFS. As far as I know, installing High Sierra leaves my boot drive on HFS+. So here is a very tentative plan:
- Using SD, clone the internal HFS+ drive to a freshly formatted APFS external volume. If I understand correctly, you will copy the recovery partition as well if I do that.
- Boot from that clone, and format my internal SSD to APFS. Clone back to the internal drive using SD. I hope that will give me an APFS MacBook with recovery capability.
- Reformat one of my Time Machine drives to APFS. Clone the other Time Machine drive to it using SD. (That will take about 36 hours). Use it for time machine.
- Reformat the other Time Machine drive to APFS and clone to it from the active Time Machine drive. During each of the two TM cloning exercises I will disable Time Machine backups so that the source is stable.

I hope that will end up with all my drives on APFS, and most of my Time Machine file history preserved.Maybe not as much history as I would like, because Time Machine is picky about cloned drives, and may recopy a lot of files that don't need to be updated and in the process it may fill the drives (currently each about 500 GB free out of 2 TB).