Just received my first set of Hataka paints Red Line acrylics, "Late War German Armor." The set includes Dunkelgelb Nach Muster, Ral 7028 and Ral 7028 Ausgabe 44, plus camo shades. The Ral 7028 appears to match the first Ral 7028 per Snapdragon's paint chips. Their Ral 7028 Ausgabe 44 also appears to be a match for the last Ral 7028 variant which is darker than the previous. Nach Muster is also a good representative match.
The Hataka paints spray great with minimal tip dry, easily corrected with a Q-Tip bud moistened with Vallejo Airbrush Cleaner. For my Iwata HP-CR (.5mm), I use 10 drops of paint and thin with 15 drops of Vallejo Airbrush Flow Improver and 2 drops Vallejo Airbrush Thinner. This ratio works great in our dry climate and the paint adheres and dries fairly quickly to the touch even with the higher ratio of flow improver/thinner to paint.
Hataka is missing the second Ral 7028 which first appeared in the Normandy Campaign. Their Ral 7028 and Ausgabe 44 are pretty good matches and are not the odd color "Ral 7028s" we're currently seeing out there.
I also have some MRP (Mr Paint) Ral 7028 lacquers coming and will report back when received and tested.