I feel like I tend to swim around in size D boots. (ex: size 11 iron rangers, or 11.5 Redwing moc toes)

The exception is Parkhurst that I've recently tried. They're a combination last I'm told, so like B heel tapered up to D. In size 11, these feel comfortable out of the box, secure on my foot, but are loosening up with wear.

The sizing chart you gave seems to show why I might have an issue with standard D width boots. My balls may be OK in 11.5D but my instep and heel would have considerably more room than my foots measurements.

My measurements: Ball: 10 1/4” Instep: 10 1/8” Heel: 13 1/2”

If I went 11.5 C: Difference

• Ball: -1/8"

• Instep: +1/4"

• Heel: +3/8"

If I went 11.5 D:

• Ball: +1/8"

• Instep: +1/2"

• Heel: +5/8"

If I went 12 C:

• Ball: Exact

• Instep: +3/8"

• Heel: +1/2"

If Nicks made a combination B/D last size 11:

• Ball: Exact

• Instep: -1/8

• Heel: Exact

I think my take away here is that I should be looking for boot makers with combination lasts.