I either unload film into different boxes or if I'm traveling and that's too bulky, sometimes I use one box with tabbed dividers for -2, -1, N, +1, +2 that I can handle in the dark. The tabs run down the right side of the dividers in order, and there's a tab on the top of the top divider so I can always keep the stack oriented properly. If it's a long trip and I'm shooting a lot of film, I can divide the stack into two or three boxes as I use up more film.
Michael Smith and Paula Chamlee use the system you've been using, but they develop by inspection. Michael claims he has never gotten a neg out of order this way, but if he ever has, he could always correct it by inspecting the neg and developing it to the proper density.