pic: Vexanum 2.0

[greencactus3]

Originally Posted by M. Krass

They can be set at any angle, strictly speaking, but the 45* offset is the most efficient choice for lateral translation. You could similarly optimize the roller angle of each well to facilitate, say, translation at 30* from forward if you chose.

going "forwards" with 45* mecanums, you'll go at about 50%, 90*, or omnis will get you 100%, and 30* will be less forward movement than 45*, and 60 will get you more than 45.
oh and the 50% is not correct if i remember a thread from looong ago