I love my AK Diffuser in combination with the Godox v860III flash on my OM-1 camera - but I never liked the velcro straps delivered with the AK Diffuser was supplied with for fixating the diffuser to the flash. Not that they do not work, but I just don't like the feel of it and the hazzel when adjusting them… 

Hence I designed this mount which just slides onto the flash and have to prongs that slips into the original velcro strap mounting holes. 

Further on I utilized some small clips to keep diffuser secure. This keeps the diffuser fairly steady - I was thinking of making an additional support that clips onto the lense and fixates the diffuser at the bottom, but I don't think that is necessary. 

No modifications needed to either the flash or the diffuser (other than you need to remove the original velcro straps).

I printed the final version in TPU, but I had some prototypes in PLA which worked just fine - but you may need to adjust the scaling some to get the correct tolerance fit - as the PLA won't conform to the flash the same way as the TPU will.

I did some in-model-designed supports to the prongs - shown in blue in the picture below, works well, and just snips off with some side cutters :D

STEP-files provided, so feel free to remix :-)