HELP NEEDED - custom adjustment to my gtk sweet-flavor theme

i us the Sweet-Ambar-Blue-Dark-v40.tar.xz as my shell theme an my legacy app theme an kora for my folders an icons

but i mis the native transparency of the Tokyonight Dark Borderless Gnome Shell Theme which i always wanted about 15% more transparent but could never figure out what lines an values in the config files to change to do so

id like some help an advice if not just tell me which lines an values in what config file an where to change in the

Sweet-Ambar-Blue-Dark-v40.tar.xz theme file to achieve this please this would be a great help to me an the look of my gnome desktop.

id like it to look like this