I take a little more air out of NeL stats than does the Think Factory. I have Irvin just a notch below their OPS+ number, hovering just below 140. That would have my Win Shares estimate in the 350 range. I also assume that there was no WWII to interfere with his career. My estimates on his stats: 2100 games, .297/.377/.492 slash numbers, which includes his actual MLB numbers.
Willard Brown is a little more difficult to estimate. His NeL stats translate in my estimation to 1600 games, .285/.350/.500 slash numbers, which I’d estimate to be around 260 Win Shares. But that has him “retiring” after a solid 1948 season at the age of 33. That doesn’t seem likely, but we have no useful stats for him again until the ’53 season when he was 38 playing in a Double A league. I’m sorely tempted to just add in Luke Easter MLB numbers, which is probably not a horrible guess. So why not? My estimate of Brown’s NeL stats plus Easter’s MLB stats gives us, 2100 games, .282/.350/.495 slash numbers and about 325 Win Shares.