There is going to be a LOT of stress where that shock attaches, particularly since it's in the middle of the swingarm. I'd do it more like this:
In fact, that's how I did it on my buggy.
The way you've drawn it will not be very strong, and need very thick tube to stop bending/breaking, making it heavier than the one I've suggested. Those two swingarms are made from some 25NB thick wall pipe for the pivot, and 20x20x1.6mm SHS for the rest. Some 6mm flatbar makes the spindle holder thing.
They have taken some serious abuse and constant 300kg's load on them and they haven't had any issues.