Parameter to set aspect ratio?

What’s the parameter to set an aspect ratio when gmod starts?

Here’s my bat:

start /high hl2.exe -game garrysmod -console -dxlevel 90 -refresh 60 -window -w 1024 -h 768

The game starts with the aspect ratio of 4:3 not 16:10.

1024 x 768 is a 4:3 aspect ratio
a 16:10 ratio would be like 1600 x 1000