+1!!! on Bruce's explaination. One thing that you're gonna learn are the principles of making pickups and how different materials affect tone are never written in stone. Once you think you know/learn something, you might get some parts that defy the odds. For example, you may design a pickup on paper based on the characteristics of materials/alloys and when you build it, it doesn't sound like you thought it would because of the tolerances in metal alloys, techniques, and winding method that you use. A pickup with the same specs built by different builders will all sound different. Yes, generally, 1010 will be warmer, however, using 1010 won't guarantee that you will make a warm-sounding pickup. 1010 might not sound warm with an A4 magnet as opposed to using an A2 magnet in the pickup formula for example. There are too many variables to provide you with a straight answer as Bruce mentioned. That is why I stated earlier to get parts and try them out. The components that you have on hand might make a warm-sounding pickup with 1010 slugs, or it might not. Try them with different screw alloys and magnet grades until you find the mix that you like. Not trying to be a smart ass, just telling you how it's done.