I didn't even run Boston yet but I got me one of these:
It's a low key, boring, grey sun visor, just to keep me focused on my 2019 BQ;) It's super comfy and prevents sweat running down into my eyes. Love it!!! I'm actually running my first attempt tomorrow and I'm wearing it... I hope it's my good luck charm... LOL
well, that's very cool. Please let us know how it goes. Good luck.