Chris. I actually do a 2 stage approach. After verifying that the struts are the same length, I JB Weld only one end of both struts, and let them settle overnight with tape holding tension. This is one of the first things I do whenever I open the kit box.
By the time I get to finish the tail (it could be weeks later in my case), I use your method of JB Welding the other ends of the struts, and let them sit in-situ until cured.