This seemingly simple question has some complexity. There are several German Naval Lozenge decal sets, the Eduard kit set is reputed to be a bit big and colors a little off. Can't say for sure if this is correct or not. References for verifying color are difficult to assess. There are black and white photos showing the relative size of lozenge patterns of some models and some of the more astute contend the smaller lozenge pattern may be more accurate. The Copper State lozenge pattern is of the smaller variety. Whether or not it is truly accurate - no clue. Part of the problem for model manufacturers is that when they make a model they need some reference and the quality of their product is dependent on their references. If a museum restores an aircraft and makes mistakes or includes some mix an match of parts it can be reflected in the final scale model product which may be proven inaccurate after the molds have been made. This is also true for decals. If someone's best guess or interpretation is based on faulty references or assumptions you get decals that may be inaccurate. Re. Copper State lozenge, when I looked at it and compared it to some photos and counted how many lozenges across the top of the wing I could see, they seemed to match up. The Aviattic set is similar but the colors are a little different and they offer different options. Some of this has to do with whether or not you want to use decals with a transparent backing or a white backing as this affects the overall appearance. I think manufacturers are doing their best but sometimes it comes down to subjective opinion. To make matters even more complicated you have to consider two more things - do you want a factory fresh appearance or a weathered appearance. These are available options. Also, you need to consider the size of your project. The lozenge decals need to cover an entire wing surface, will you have enough coverage length and width-wise using a single sheet or will you need multiple sheets? The decals come in several formats like A4 and A5 and some non-standard sizes. There are other company's making the Naval lozenge, some long gone like Americal Gryphon which were know for some healthy research. Look around a bit and decide, maybe buy them all, do your own research until you are comfortable with your choice. Ultimately, you should probably build for yourself - your completed model will be displayed in your house and you have be happy with the final result - unless you are a professional or building for competition, nobody else is going to see or comment on your work. I probably haven't answered your question but perhaps given you some food for thought.
