I designed this battery strap mount for the bottom plate of my Squirt v2 so I can mount my Osmo Pocket on the top. It uses the 30.5x30.5 mm holes and fits over any bolts heads that are in the 20x20 mm holes. I had to design a custom mount as I am using the 20x20 holes for the stack and I needed to make something which would fit over the bolt heads.
The 5 mm thick version has a slot for the strap that is deep enough to adjust the strap position easily. There is a square recession for velcro or Ummagrip. It has recessions deep enough to cover cap head bolts in the 20x20 configuration. This is what I am using now as I don't have button head bolts for my stack at the moment.
The 4 mm "thin" version has a shallower slot for the strap which won't allow most straps to slide easily. It has recessions deep enough for button head bolts in the 20x20 position. I haven't tried this version yet.
Both work best if mounted with M3 button head bolts which will not protrude above the mount and touch the battery. Cap head bolts (as pictured) will touch the battery.
On my machine I have to print hot (228C) and slow (5-8 mm/s) so the filament moves smoothly though the nozzle and doesn't clog. The D6 has a ~3 inch gap between the extruder gear and the hot end where the filament travels through a 2 mm hole bored through the gantry block. Unfortunately that seems to be enough to allow filament bind-up if the hot end isn't 225C or hotter.