Setting Toad NLS_LANG when using Oracle Instant client in Windows

When I use Toad (any version) with the Oracle Instant client i usually get mixed up session NLS parameters. When i have some kind of Oracle development tools i need to edit just NLS_LANG registry key in my preferred home.
When i use instant client easiest way is to edit directly through Toad:

First step is to click on the 3 dots near Oracle home used. If NLS_LANG is empty double click on it and answer "Yes" to "Are you sure" question, Enter the preferred NLS_LANG and Toad will populate required Oracle keys in the registry.