Who'd won this classic I know that the Spinks Jinxs had 21 ko's and M.Spinks could box, but I think Holy would be to much for Mike and win in 15.
Evander isn't getting knocked out by The Spinks Jinx, and he'd most likely be able to outwork, outphysical the weaker Spinks to a clear UD. Maybe a late stoppage but Spinks was never even dropped until his last fight with Iron Mike, he'd be able to last the distance.
I think picking Holy by a decision, is probably a fair call. Although I think its possible that a more experienced Spinks between 1986-1987, could have conceivably outslicked Evander to a decision himself, especially considering his awkward style. We also have to consider that Spinks competed very well both above and below the cruiserweight limt, therefore 190 Lbs may have been an ideal weight for him. I think the real key to this matchup is the timing of its making. I firmly believe that a declining Spinks in 1988, would have lost to a peaking Holyfield at both heavyweight and Cruiserweight. However, had these two met a year or two before, when Holyfield's career was still in the embryonic stages, Michael may have barely pulled it off. As you say, Spinks' durability is rather underrated. He was dropped by only one man. That fight came in the very last outing of his career, and against a virtually unstoppable puncher of a champion. Frankly, I think Spinks could have reigned for a very long time at lightheavyweight, and possibly could have taken a few belts at cruiser. Overall, I rate Evander the better of the two, and would have likely picked him most of the time. But matching these two men anytime around 1986-1987, might award Spinks the slight edge, due to experience and proven abilty at two major weight classes.