What? Canadian invaders already? (Hello Bernie!)
And Re the tubes, I tried them after reading your website and they are indeed worth their weight in gold.
FWIW, for anyone wanting to try these, large plastic soda pop bottles can be used to similar effect. I cut the bottoms off with scissors and leave the tops open without a cap–they work fine on shorter plants. It is also possible to cut off the tops (necks) of the bottles and tape several together to make longer tubes, but the real tubes (I purchased mine from a vineyard supply) are easier to assemble if you have a lot of grafts.