The plugin almost works, but there are a couple of annoyances, the most major one for me being it returns results from techknowhow.com rather than my https://tech-knowhow.com it seems it hasn't implemented googles 'site' search quite right.
Also the edit button next to the 404 link does not work and honestly I'd prefer my sites results (if it was the right site) to come up first. Chance are they were looking for something that is still on my site with an incorrect URL or spelling mistake. Those things fixed, I just might install this as I've been looking for almost exactly this plugin for a while. 2 Stars at the moment, 4-5 stars if it worked properly. This plugin has potential.