My experience for reference - I followed the general forum advice on roughly 1/2 dozen Barrie lasted shoes. I discovered that in order to get the perfect fit, I actually had to size down even further. My regular size is 10E. I ended up at 9E on both the Barrie and Trubalance last. I have low and wide feet.
There are a few things I did not account for in my original sizing that perhaps can help others new to Alden
1. Wearing thin merino wool socks leaves extra room in your shoes. If you are used to wearing thicker socks and switch to thinner Marcoliani argyles, you should account for this in your sizing calculation.
2. While cordovan does not stretch, the insole of the shoe conforms to your foot after a few wears. Your foot ends up a tad bit lower in the shoe so the effect is that the shoe feels a bit looser even though the leather has not stretched. All of the Alden boots/shoes I purchased in 9E felt a bit tight across the top of my foot the first few wears and then loosened up. I would not extend this logic to the fit of the shoes as it relates to the sides of your feet.
3. The Alden combination last means the heel of the shoe gets larger as you go up in width. This makes getting a perfect fit difficult but not impossible for some of us whose foot width is not matched by heel girth. Where possible, I get Alden boots now since they tend to mask the issue of the heel not fitting as perfectly as it should.
4. I have noticed size differences between various Alden shoe styles. For example, the cap-toes on the Barrie last feel a bit tighter to me and did not loosen up as I though they might. I eventually sold those. Plain toes feel a bit looser to me. Calf/Suede stretches out a bit more.
I would suggest there is nothing quite like going to the store and trying them on yourself to gauge the perfect fit. Do not compromise on fit irrespective of the beauty of the shoe.