Per Peter Smith's excellent comment - I thought of the same Analog Devices "report from the tranches": Optimize High-Current Sensing Accuracy by Improving Pad Layout of Low-Value Shunt Resistors by Marcus O'Sullivan (here available also as a pdf).
In short: you will need to experiment. The results will also depend on the copper weight of the PCB, the tempco of the resistor, the amount of solder paste used, the type of reflow process used (IR vs vapor phase), etc.
In my limited experience, I had excellent Kelvin behavior with solder paste coverage near the minimums and solder-phase reflow. But it's a trade-off. The measurement accuracy of such SMT-mounted devices is often at odds with longevity, i.e. the soldering/reflow settings for good accuracy may have low yields and/or low durability.
The ultimate answer depends on what do you need: what are the actual specs? Temperature range? Allowable system-level tempco? Current range? The volume you have available? Etc.
For very high currents I've used crystal cans as current shunts and quartz crystals as highly accurate temperature sensors. But that's by no means some ultimate solution: it worked in the narrow niche I needed it for.
For resistances in the <0.1Ω range, PCB traces offer a lot of flexibility in tuning the Kelvin behavior, especially since they can be very well modeled using basic finite-element methods for 2D resistive sheets. As long as you can measure their temperature well, copper isn't too shabby a material. Having very thin temperature sense traces interwoven with the sense traces may work. It really all depends on how much calibration and characterization you can afford.
If this is a low-volume product or a one-off that doesn't have extreme volume constaints, I highly suggest using actual Kelvin sense resistors that have four dedicated terminals - whether SMD or through-hole.
There are some truly excellent Kelvin sense parts both in through hole and SMD, and you get what you pay for in terms of long-term parameter drift, tempco, voltage coefficient, etc.