How old is the nephew? Could you accent the quilt with some appliques that are age appropriate to cover the worst of the corners? There are so many fun fabrics that can be fussy cut for all age or hobby groups. And, by the way. The points you are agonizing over won't really be noticed once the top has been quilted and washed. We are our own worst critics. Give him this quilt and when you want to, maybe a few years down the road, make him another one. He still won't see anything but the love you put into making the quilts.