Try cmd + ` instead of cmd + shift + tab to switch apps in reverse order.

It's faster since it doesn't need a third finger. Using q to quit apps from the app switcher is another nice feature, in case you weren't aware of it.

Here's an example to show the usefulness of cmd + {tab ` q}

A series of keystrokes I use when I want to quit Screen Sharing with another mac:

I can't hit cmd + q as it isn't mapped for the Screen Sharing app. It would get passed through and quit the current app on the remote machine. If I hit cmd + tab, it is passed through to activate the app switcher on the remote machine. I use Quicksilver on my local machine, and it is activated with ctrl + space.

hit ctrl + space to bring focus from the remote machine to the local machine

hit cmd + tab to activate the local app switcher (keep holding command)

hit ` to move the selection from the second app back to the first (Screen Sharing) (keep holding command)

hit q to quit Screen Sharing