I have both. W+H are pretty decent, but to say they are equivalent is wrong. I also have A.P.C.'s. I probably have too many pairs of jeans.
W+H has much better denim and while the fits are similar, aren't exactly the same. APC's diaper ass is too much for me; it's this weird combination of loose butt plus low back rise, leading to my actual ass always falling out of it. My beat up NS's will be my last APCs. Just not worth it anymore.
Same experience as you with APC denim Nil. Think it's that the waist is just too big at least on PS. Tried to fix it with PNS but it was worse. Higher back rise with same large waist. Ordered from Artist denim in PNS rise but tighter waist, it might work out.
wrt fashioning and above jacket, don't think it would've been too bad if it was fleece with large cells/grains (? don't know term). But that's not what it's like so whatever.