I'll be honest here. Even when I played a lot with config files and read the whole MS-DOS manual at 14 years old, I still have not idea about how memory works. When I had "out of memory" errors I simply tried combinations like "DOS=HIGH,UMB", "DEVICEHIGH=", "FILES=40", etc. without knowing its true meaning. If anything didn't work I simply gave up, it was not like I could run anything important with only 4MB/8MB of RAM anyway. Then WinME came and forgot all about that. I can't even remember how I managed to run NEOGEO driver with KOF9x on MAME with my crappy 486DX PC, I only remember I let it loading before going to sleep and the thing was finally running at 2 or so FPS the morning after.
Maybe it's time to give it a try to such missing concepts now that I can freely adjust memory with a ramsize parameter, instead of fitting 4 same size memories in slots. But for now I can't be of any help.