Here’s a picture of my Gaui 425 – including a scale (cm), with and without canopy [the carbon version, not the cheapo one] as an “X-Ray image”. Just in case that someone out there is (like me) currently trying to figure out which batteries might work for this bird. Special feature: 10 pixels in the image’s original size (download from here; 2,1 MB) roughly correspond to 1 mm.
Currently the only mod done is the canopy retaining bold which is mounted on a 2.5 mm plastic plate facing down. I will probably remove that altogether – if the battery’s big enough, it can’t slip anyway.