I have a very hard time buying good shoes in person let alone online. Always have- I shopped at vans shoes in Orange County as a kid who couldn't find size 12 comfort. So my feet measure left: 14 and right: 14.5
I ordered 15 which is usual for me, these fit perfectly-  that extra whole size difference on the left can be noticeable. Not In this case tho, they really are a perfect fit for both feet, which is really unusual For me and I like the way they feel. Light but supportive in all of the right places, the only way I can really describe it is it feels like there is an orthotic. With Merrell I have good luck. Quality
And lightness are paramount in selecting size 15 shoes as a pair of them often weigh quite a bit. Thanks Merrell Shoes