Due to the lack of detail in the Wing HGs and very limited articulation, not to mention the polycaps that are exposed in the elbow portion. A big downside to the HG Tallgeese and all the wing HGs is that the elbow joint is made of two polycaps with rotation at the junction between the two polycaps, not like the newer 1/100 no grade kits which are sandwiched between other plastic parts also the rotation is at the upper arm.
For this build, I would use an MG God Gundam inner frame because I really like the stability of the joints owing to the screws that hold the inner frame together. The problem is the proportion of the HG Tallgeese to the MG God Gundam, the God Gundam is about 1-2mm smaller than the Tallgeese, with this said, I would have to extend the legs and arms of the inner frame. I also named it "Maelstrom" because the Tallgeese 3 codename is "Wind" and I am planning to give the kit a "Knight" feel because it looks like a cross between a Spartan and a Sinanju. Hehe. I'll be updating every so often.
Thanks for reading!