I just did the pin+airhole block switcheroo between V1 (2k16) and V2 (2k18) and they are identical apart from the hole size.
Another unmodified 2k18 is already in service but I'm not able to make any exact flavour comparisons with the SXK 2k16 since I'm using different wire and juice. The AFC ring moves smoothly in both V2s with just the right amount of resistance. All the magic happens within the last 1-2 mm when AFC is nearly closed. More open than that and it's restricted DL territory.
Size wise the V2 is practically identical to Dwarv V2 3.5ml kit (both are flat tops too).
Compared to the Doggystyle V1 it looks only marginally (1mm?) taller, but the V1 looks more slender with its top ring.
The V2's drip tip well seems identical to V1's in terms of fit and depth, but being a flat top I feel slightly taller drip tips work better with it.
The removable top cap isn't threaded but held in place by a healthy o-ring. Still my first instinct has been to try twisting it...
Usually trying out a new tank involves some level of surprise, but apart from the top fill design the 2k18 is practically identical to Doggystyle V1 except it's probably closer to the SMJY version than the tighter SXK. Swap in the pin+airhole block from the older SXK and I'd expect them to be the same.