I am using Tinkercad. Mind you, it's not just shrinking the height that's the problem. Depending on the design (like if it fits over a lip or is "multi-tiered", you might end up with either too little plastic left (weak, thing ceilings, floors) or the measurements are off. I am not saying it can't be done and yes it seems really simple but I just had issues. I might just stick with the one Kludge made and try to account for the extra spacing with the adjustment screws. I hope they have enough travel.
Edit: What was your shipping cost for the 9x6 1/4" glass from McMasterCarr? Also, does anyone know if the bed sizes for the Qidi differs from the Flashforge? All the corner brackets I have seen on Thingiverse are designed for glass that is too small for the base. Like people buy 9x6" glass but the bed is slightly larger so it creates like a lip. So confusing. Here's an example -
http://www.thingiverse.com/thing:613685