The problem with win 98 is that sfall functions do not work under it. Newest sfall does not work under XP AFAIK. the best way to have any kind of Sfall running under win 98 is to use Crafty's Sfall2 version. Not exactly sure if he has a tutorial on how to make it work under win 98 for Fo2 like he did in his Sfall1 for the original Fallout. If You however struggle with efficiency on android try ExaGear RPG app for android. should run much smoother. If still running slow try to find out about your embedded GPU on your device. apps such as CPU-Z and SoC-L should help there. if SoC-L lists under gpu around 70-80 GFlops or more you can try to force 2D rendering on GPU in android's developer options. It really helps to boost framerate wether dosbox or ExaGear if You have a good GPU unit embeded, at the expense of battery uptime.