My Spud Struts are pretty straight, Mike.
I think the photograph above contains a bit of an optical illusion.
In any event, the 1/4-inch thick, steel bar is very strong, and any curve in the bar should be stronger than the bends in the TT braces.
If a slight curve is present in the left Spud Strut, it is caused by the different angles of the bolt mounting brackets for the battery box, and these angles might be unique to each XR650L motorcycle. Any curve in the right Spud Strut can probably be corrected by adjusting the length of the tab needed at the front of the strut.
Others might disagree with me, but I don't think it's necessary to mount the rear of the Spud Struts to the rear blinker holes. The blinker hole bolts are pretty small, and a lot of items are connected to them already.
In addition, a longer, left Spud Strut would have a different mounting angle that would probably cause intrusion of the strut with the stock battery box. Lengthening the right Spud Strut might cause it to intrude on the muffler.