Planting A Hedge - Part 1 Planning It Out

I guess I am someone that likes boundaries, I like my garden to have a fence and my fields to be separated up.

The footpath that runs across the top of our land wasn't a big issue for me, but I always knew I wanted to separate it in the first field as this is where our children are likely to play and the majority of our "free range" (or escaped) animals are likely to be. Also as this is the area that contains our sheds and shipping container I'd like it to be a little more private, although the footpath isn't heavily trafficked, everyone like to have a look at whats going on.

An ignored piece of advice

 My simple plan is to plant a hedge along this footpath to give a clear boundary. This will be fenced both sides (possibly), with a double gate right at the start (but that might have solid fronting to it and be 6ft high to protect my stuff).
I've decided to give a 12ft corridor down the path as this give me good access with a tractor to the next field and also allows it to be mechanically cut if I want it to be in the future, I know I'm loosing grazing space but the trade off for privacy is worth it (I can still run animals up their to graze it if I want anyway).
The trouble is, what hedging to plant? I've been reading the relative merits of them all, evergreen, beech, yew, native, etc. But I've decide that I'll plant a mainly Hawthorne hedge, with holly and any other native hedging plants I can find seeded down either here or at Mum and Dads.
I'm going for mainly Hawthorne as the total run of it is 42m so that will mean around 250 plants and as I'm not going through any grant schemes this way is lightest on my pocket while still giving me the results I want.

Don't know if you can see the pegs and the blue bit of string to mark the hedge or not. I've marked it a metre wide

The far end of the hedge will also have cider and crab apple trees planted every so often to make productive use of this space but not with a fruit that's too desirable to walkers!
Anyone else planted any hedging and have any tips? I'll plant it as a double row and aim for 6-7 plants a metre.