I would think a reverse trike. I might imagine a 300lb buggy+driver may have structural issues with a top-load config and I'd rather front-load into a reverse trike than stretch over a damn steering into a standard trike.
But anyway, I'm assuming an alumni buggy build will still be a closed process. As much fun as it would be to have a picture of alumni from 8 teams building a buggy together in harmony, filming the process as a learning tool for teams starting out, I don't think that will happen.
Bordick: 'Oh, you guys use XXX? Wow, that must make the buggy like 3x faster!'
<Stab Stab Stab>
Bordick: 'Et tu, Hate?'