How many lumens for 25 MPH
I'm a heavy commuter and my schedule has shifted. I ride almost the entire ride on streets with cars; about 3/4 of the ride has a healthy shoulder. Come fall I'll be riding in the dark. My current max speed is approximately 27 MPH with an average around 19 on a MTB uglified conversion. I have a set of ghetto lights now that let me roll at about 10 MPH for after work emergencies. However, if I'm going to keep commuting I want to be full speed in the dark. I was wondering what kind of Lumen output I would need to consider (ballpark), since it seems to be the most important part of the package. I understand lens, reflector, etc. make a difference but any advice on sheer light would be appreciated.
My budget is ~300 USD$, with a stretch if really warranted. I like the idea of LED with a conversion for night running...but that's a secondary motivator.