Poor Ajax scouts, their match was cancelled today because of snow.
Helenius is certainly in the top 3 strikers in the Danish league and youngish, but I have a bit of doubt if he would make it at Ajax. Despite his height he's not that fantastic with his head, which is weirdly enough kind of his weakness with him being nearly 2 meters. With Cornelius you would get both great header and as good finisher as him + he's two years younger.
Helenius rejected Sporting Lisbon this summer btw, he seems to weight first team action very highly and would rather stay another season than sit on the bench.