Windows in Pony Walls-How do I set window to cut walls correctly and trim?

[gravattedesign]

Good Forum Gurus,

I have a Log Cabin Lakehouse addition with the Log walls over a Foundation Stem wall above grade at the basement level. Windows need to cut through both the 10" stem wall and the Logs. How can I get this to work? I've checked on the casing options for double walls but it occurred to me that is not a double wall. I appreciate your consideration and advice.

 

File accessible via Google Drive

 

https://drive.google.com/file/d/1a-61hszDlQr9ELEvpoI1ZFnPvg4KY4fp/view?usp=drive_link

 

[Rosco2017]