Dual gps unit GoPro mount

I use a Dual universal GPS receiver for track days on my motorcycles and cars. It allows 5hz vs 1hz processing from an iPhone using Harry's Laptimer Pro. Much more precise lap times. I have go pro mounts on the vehicles but could not find a suitable method of attaching the Dual unit. I undersized the parts that mate to the gopro mount so there is less finishing needed to fit. I use a Makerbot Replicator 2 using PLA and printing vertically.