Well done gury and wahaha (ima ncase and guniq fan)
This case is quite ideal for those who prefer more features of ATX board in as sff as possible, I am one that like to consider this sff atx.
I have a modivio 3d printed case to test if i liked the form factor, it is 370 x 270 x 95mm, and allows gpu of 245mm length, 42.5mm thick (very few 1060 cards within 245mm, but 1080 mini cards aplenty)
i figured bigger 300mm gpu would be thicker like 57.5mm, and wouldnt fit above atx board
Maybe you can consider a 80x253x346 version which will be 7litres (for the 7litre lovers) I'm willing to take the 8.5litre though