Kiwi contains an alcohol base and eventually dries out the leather (much to it's detriment). If a good shine is required, use Lincoln black shoe polish instead (lanolin base). It will achieve about 90% of the shine of Kiwi without the negative drying effect and will actually 'soften' the leather to ease break in. It has served me well through the years and has kept a lot of boots that would have been tossed (if using Kiwi) to remain in the inventory. Do your best to only apply solutions to only one side to permit the leather to 'breathe'. "Sealing" both sides of the leather will accelerate it's destruction dramatically. Typically, you will not encounter this opportunity with footwear, but belts, holsters and other leather gear do. If anyone has any information about or negative experiences with lanolin based products, clue me in, since I am dumb and happy at the moment. Also, some info on the other products (Nix Wax/Chelsea Leather Food - source, cost) would be much appreciated. I see too many shooters/hunters spending $2500 on a rifle and not bat an eyelash yet grunt like ogres when they see a $200 pair of boots. Same guys show up with $30 hiking boots in inclement weather for an elk hunt and wonder why their feet are always wet/cold. The importance, value and neccessity of excellent footwear should not be underestimated. If I am trashing my boots, I need to find out sooner than later.
As a sidenote, I am really surprised you former military types did not offer a single tip on how to achieve the 'ultimate' spit shine!