Thank you Martin. I ended up using the parameters below in my powershell script:

$session.AddRawConfiguration("Logging\LogMaxSize", "10485760")
$session.AddRawConfiguration("Logging\LogMaxCount", "2")

You can set Configuration\Logging\LogMaxSize raw configuration option.
https://winscp.net/eng/docs/rawconfig

Hello. I'm using the sample powershell script from here https://winscp.net/eng/docs/library_powershell

I'm able to generate my log using SessionLogPath but is there a comparable option to /logsize so I can set the number of log files and their sizes? Thank you kindly.