Adjusted stats are nice to give us 'ballpark figues' for historical purposes, but they're not accurate in themselves and, anyway, I don't really need them when I've seen both players at their best.
As I said, it's basically splitting hairs between Lemieux and Ovechkin, for me, but I still take Lemieux. Their goal-scoring beyond age 30 isn't a very important factor for me, anyway, as my main point of interest is the respective player's prime.
Between 1986-87 and 2000-01, Mario scored 557 goals in 636 games, or 0.88 goals per game over an almost 8-season span (albeit with huge breaks for time-off, injury, retirement, etc.). He did this while scoring at a 171-point pace.
From 2007-08 to 2015-16, Ovi scored 427 goals in 676 games, or 0.63 goals per game. He did this while scoring at a 93-point pace.
Giving Ovechkin every 'adjusted' advantage here, at best their goal scorinig will come out even (though I'm not even sure about that), but meanwhile Mario piles on about 65 more points per season than Ovi.
For extended, longevity of elite goal-scoring, I don't think there's any doubt now that Ovechkin is #1 in NHL history (he has now surpassed Howe and Richard and Hull Sr.). But I don't really care about extended longevity in player comparisons. (On the other hand, I do care about having a long-ish prime, which is why Brett Hull or Wayne Gretzky don't rank above Ovechkin.)
Anyway, it just depends on what aspect you value more.