After logging into the launcher, before you click on play, click on the small cog wheel icon located after your account name, then click on Manage Profiles. This will open the migration tool which will allow you to migrate your client settings from previous installs by dragging and dropping the settings you want from the left window into the right window.
Once you have drag and dropped the settings you want from the left window to the right window you should give the profile a name. Once you have given the profile a name click the close button. Click on the cog wheel again and select the profile you just created to start the account with those settings.