smallest form factor to get RANE 12 mk 2 to talk to Traktor pro 3 (or upgrade to 4) for DVS

I assume that this is different now because of the scratch deck. Sorry, that's the only way I know it. So here's a tip from me: display the phase meter in the deck headers, there you can see if the phase is shifted and which side you need to correct it on. Alternatively, you can just double-click on sync and then the phase jumps back to the grid. As soon as the grid is correct again, the sync button lights up blue again. Otherwise, only the text is blue. This is probably intended as visual support.

Ah, ok, I understand what you mean. Unfortunately, I can't help you much, as I don't know much about controllers. I only need my S4 for a few gigs a year, where it doesn't make sense or there's not enough space to lug all my equipment around. I'm more of a turntable person, and I'm happy when I can do as much of it myself as possible, and can also do things that are deliberately inaccurate or unsynchronized. I usually correct the phase using the turntable or jogs themselves, or by double-clicking the tempo sync function. I let the grid jump to the phase briefly and then deactivate sync again. I do this whenever I've been inaccurate or done complicated things and need to get back to the grid more quickly before I can hear or realize where exactly I need to correct something and in which direction. Perhaps this is a workaround for you, or a matter of getting used to it. If you run out of the phase after scratching, you can deactivate sync again and then activate it again straight away. So just a double-click. In my case, it has now become embedded in my muscle memory.