Using DSLR with a tentacle box results in 2 clean channels for me - LTC on L, and clean reference audio on R. My workflow is INCREDIBLY faster than previous audio only synchronizing.
I purchased 4 tentacle sync boxes a month ago. I use them on small shoots where I'm responsible for Video and Audio recording - the whole thing. I run 3-4 tentacles: DSLR. Audio Multitrack (One track LTC), and Stereo Safety Record (plus 3rd track of LTC). Everything syncs instantly in the Tentacle Sync Studio software, and I output XML or AAF which opens flawlessly in Premiere and Logic Audio, or I can actually transcode Video and Audio with digital timecode added to the video and audio files.
EDIT (4/10/2019): I lied. 🙄 Well, about the clean DSLR audio channels anyway. My DSLR is a Nikon D810. The workflow does work very well, but the mic sound recorded on R of the DSLR is not completely clean. I do get a very small amount of bleed from the timecode into the reference audio recorded on R channel in DSLR from the tentacle's built-in mic. In my case, the timecode bleed was so soft that I didn't notice at first, and the reference audio is perfectly suitable as reference. At this point, I don't know if the L-R bleed problem is in the tentacle or in the Nikon. Tentacle sells a L/R split cord, or you can buy a cheap one on amazon to input 2 separate sources into the L & R 1/8" TRS input of the DSLR. I plan to feed LTC from the tentacle and reference audio from a separate source like a wireless receiver to see if I still get bleed.