Hedge laying- beginner questions

I'm in zone 4 in BC, am just learning about hedge laying, and have a few questions. Can any coppice tree be laid like this? What is the min/max trunk diameter for laying? When to coppice vs lay?

Also, how wide (broad) do people make hedges? Because of fire I don't want to use conifers but I want a hedge that's visually opaque in the winter  and am allowing 10' of depth but would appreciate others' thoughts.

I don't know the specific answers to your questions but i did find this video interesting.

Hawthorn is the classic for a reason, it lays well and gets dense enough to be visually solid in winter once it thickens up over a few years. For fire resistance deciduous is the right call anyway. I've seen people combine hawthorn with hazel, the hazel fills in faster while the hawthorn does the long-term structural work.

I've never seen a laid hedge 10 foot thick Lawren, and I don't know how much you'd actually gain by it. Most of the fresh growth would be in the sides of the hedge as the inner and lower branches get shaded out (hence the need to re-lay the hedge every few years). The act of laying makes the hedge dense so even 2 - 3 feet gives a good screen. Some broadleaved leaves retain their leaves over most of winter (and some are evergreen) Oak and Beech are the ones that come to mind as retaining their leaves here until spring sometimes. I don't know whether that is helpful for your climate though.

Montgomeryshire style hedge newly laid - image from UK National hedgelaying site

You might find the UK National Hedglaying site useful here for example is an explanation of different ways of laying hedges.