I dont know about these hubs specifically, but as a rule it is usually better to get the right hub for the frame.
Trying to modify axle length is often at odds with the hub shell design, and leads to disappointment
Is the axle 145 mm long, or is the OLN 145mm? I was of the understanding that the hubs came in 135 OLN for standard 135 mm spaced frames and 140 mm for WTB spec Phoenix etc.