First, it just depends on your fuselage!!! Since this Vee Strut bolts to the wing mounting brackets - the holes would have to be approximately half an inch inwards than the lower longeron for 23" to work, I guess it would all depend on how you made these brackets... But you'll build this part to your airframe (so I believe 23" is just approximate as you'll find several places in the drawings)... Mine is 19 1/8" but my fuselage is only 22 1/4" wide... 20 3/4" looks correct from your 2nd picture.... Looking good BTW....
