Replicate sftp -B -R Performance in WinSCP?

Hello to all,
I use scripting WinSCP to transfer files to a mapped SMB network share, and my speed is capped at ~3 MB/s. I know this is not ideal but I've discovered that the native Windows sftp client is faster (~12MB/s) if I use these flags:
and then perform a get.
My question is how to get the same performance in WinSCP for my scripts. Is there any equivalent flag for those flags?
Thank you all

The -B maps to SendBuf raw session settings:
https://winscp.net/eng/docs/rawsettings#sendbuf
Though it affects uploads only. Are you sure 8MB helps or even works? The standard OpenSSH does not support more than 256 KB. Or maybe the Windows version is modified somehow.

The -R maps to SFTPDownloadQueue and SFTPUploadQueue raw session settings, which are already higher by default, 32 and 64 respectively. And actually even OpenSSH sftp defaults to higher 64. Or are you saying that decreasing the requests/queue increases the transfer speed?

Hello Martin,
I have a performance issue that I'm hoping you can help with.
When I use Windows File Explorer to copy a file from my local C: drive to my mapped network drive S:, the transfer is instant. The S: drive is a high-performance Azure File Share (SMB).
However, I see a huge speed drop when using a WinSCP script.
1. Fast Scenario (Downloading to Local C: drive):
When my script downloads to the local drive, the speed is excellent.
Command: winscp.exe /console /script=C:\temp\myscript.txt
option batch on
option confirm off
OPEN sftp://xxx:xxx@xxx.local -hostkey=*
LCD C:\Apps\
Result: Speed is 30+ MB/s.

2. Slow Scenario (Downloading to Mapped S: drive):
When I change the script to download to the network drive, the speed collapses.
Script line: LCD S:\Apps\
Result: Speed drops to ~3 MB/s.

This is strange because, as I mentioned, a direct Windows copy from C: to S: is instant. It seems the bottleneck is specific to how WinSCP writes to the SMB share.
Is there any way to configure WinSCP to get the same high speed when downloading directly to the S: drive?

Thank you.

So with OpenSSH sftp you get good throughput even when downloading to S:\?