The V2 Clean is proabbly at least 1 and maybe 2 complete steps or levels below the UI in oil handling capacity. Unless polished a good deal, the UI needs a lot of oil, I'd suggest nothing less than true medium-heavy oil, while the V2 Clean is more for medium-light oil. So, little wonder that your V2 Clean was outhooking the UI; the UI had to be "strangled" in that much dry.
I agree with Inverted - drilled a little less strongly, but by no means weakly, the UI, especially with some polish would be more versatile. Most balls can be made more versatile by lengthening the pin-PAP distance to the 4",possibly the 5" range depending on your hand and ball speed, and the pin's position above or below the bridge AND the ball's core's dynamics.