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Decals ready to go Karl, will be in the post Friday...."Red 22 and the Werk Nummer 490044"
You have to fix the tape so that it pulls each wingtip inwards (and upwards of course), keeping the tesion. That Bf109 in the pic has a wingspan, in that scale, not far off the 1/72nd Connie, and I've used the method for over 40 years, on much longer spans, without a problem.
It's possible, and likely, that using a weight on the fuselage will give an uneven dihedral, as the weight settles and the glue hardens at different rates. Also, it can cause uneven joints, which then need filling.
Nice job Rob. £cm and 2/8th ? Mixing metric and imperial is confusing! 2/8th = 1/4 = .25. Ah, Got it ! 3.25 cm !!