No, I have never used Nitty Gritty Products, but have a good friend who has, is actually a competitor of Nitty Gritty, and has told me that thier products are exceptionaly good, hold the majority of the record cleaning market share, and probably for good reason.
To the original poster: I honestly think you might be taking a large step backwards going to a DIY Brew, unless you are going to concoct this formula with the highest quality ingredients, and paying strict attention to mix percentages, etc. There's no magic, no snake oil, or luck involved, it is pure science.
I am a very happy user of the AIVS cleaning system, and will continue it's use. With that being said though, I don't feel anyone should rely on any one, or even multi step cleaner, and expect a residue free surface. A final follow up rinse with high quality pure waters will make a substantial improvement with any cleaning product.
Lastly, many times, these fingerprints, grease, and other contaminants have been deposited on the record's surface when Ronald Reagan was in office. They often have left damage from acids, where they have literally eaten into the record, and nothing, no matter what a product will claim to do, will remove this damage. It is permanent.
It can be at times, be only just a visual defect, and may, or may not have an impact on the sound. Mark