I didn't watch the whole video but one thing I might add is to cover your floor with an old sheet to catch the overspray. It is really hard to get 505 spray out of carpet. Ask me how I know that one.
I have been spray basting quits on my design wall. I cover the wall with an old sheet and put the quilt back on it. i stick a few pins in to hold it up. Then I pin the batting over it. I spray baste it. I start in the middle and spray it and do the top half, then the bottom half. I do about 3 feet at a time and smooth as I go. Then I add the top and do the same thing. It works really well. I plan to fix it up so I can do this down in my basement.

[QUOTE=true4uca;7952845]It’s tumbling blocks.

That's essentially my basting method too, except I use Elmer's and a warm iron to hurry it along.

[QUOTE=true4uca;7952845]There is a link in the description below the video on how to make the Y seams, which gives the measurements of the blocks. 4 1/2" ruler 60 degree ruler. Blocks are cut from 4 1/2" strips.