I am not using the alum. struts . I am using Balsa USA shaped wing struts.
https://www.balsausa.com/store/categ...id_category=31.
1/2 x7/8 on front
3/8 x 5/8 on back
And misterbill is right if you use k&B run a 4.40 rod threw it. I would also put a little epoxy and mircoballoon in each end.