Boy, posts are few and far between on this thread! Guess not many have gotten into EAA that much in Oz? Or everyone is out there having a blast and don't need to post?
Re focusing ... that video in the last post was one of mine, but doesnt really show focusing. Here's one I made quite a while back which shows a home made bahtinov mask which works a treat, and it shows it in use. And another which shows you really don't need a full size mask with a cutout when using a SCT ... a smaller one hung around the edges works just as well. That tip is especially useful if one is using a hyperstar on a SCT. BTW those flyscreen ones are much easier to make nice and small to allow focus using a DSLR lens. Having said that, if you either don't wish to make one, nor buy a commercial mask, then zooming in the liveview (if your Canon has that liveview) and moving the focuser of OTA or lens until the zoomed image looks as small as you can get works well too.
https://youtu.be/IeUs7pFwMJw
and ...
https://youtu.be/r9HPXvhw6ZQ
cheers