I agree with Minwah here. I believe you should just setup windows 98 to run in pure dos once you have everything set up properly. Gamelauncher or ArcadeOS are excellent choices as well. I too tinkered with mame in dos but unfortunately couldn't get sound to work properly.
I would however, suggest you start your testing with mame 0.106 and move backwards if you have speed issues. an 800mhz processor back in the 0.106 days still allowed you to play quite a few games on the 0.106 compatibility list and because this was the last version using the old rendering engine, you have the option of running the most games without needing a greater overhead in processing power. If you are having speed issues from that point you should start testing older versions of mame below 0.106. It's just my opinion though.
If you plan on using gamelauncher, here is the rom file builder which is very rare and no longer located on the gamelauncher website. It took me a very very long time to find this.