Our predefined maps are pretty solid, it takes an extreme cirumstances to need to bother with map6 at all. You're not likely to make anything stronger than our existing maps.
Pretty much the only Map 6 uses I've seen, and for my own, are to make a map that is between one of the pre-made ones or to tone down a pre-made map. Mine is more like a Map 1.5. I prefer the way Map 1 feels normally driving down low but wanted the stronger top end and higher peak boost of Map 2.