Hornbeam, beech and laurel can all be used for hedges and can easily be kept three feet wide, let alone four. But you have to keep up with the shearing and for 80 feet that would be a lot. Google will provide hundreds of examples. For a formal hedge I'd keep to a single variety both for uniformity of appearance and to have it all on the same clipping schedule. Against a fence can work but is not ideal. As to planting distances, again, Google will give you instructions.

Floral thanks for the advice. Initially I thought laurel was the ideal choice because it could cover the sun and shade stretches and it’s evergreen but i thought maybe hornbeam would take sheering better with its smaller leaves and look prettier. I think you’re probably right though and not to mention skip laurel is easier to get a hold of than euro hornbeam. Skip laurel also grows quicker which is nice. It’s a long story but if the hedge takes off I may convert the picket style fence to the one in this picture which I have in the rest of the yard. Perhaps this would make the hedge nice on both sides.

I thought you meant a solid fence which would keep light off the back of the hedge. Pickets wouldn't be so bad.

I yes I do currently have a solid fence, this is it here in the picture. Id maybe switch it to the kind in previous picture as a kindness to my neighbor so they don’t have to look at two different styles. I currently have skip laurels and they’re all in a decent amount of shade and doing fine aside from some that were heavily deer grazed. I know Laurels are a popular plant but looking them up all I see are problems people have from not being quite hardy enough in zone 6-7, to winter burn and disease. I worry this combined with sheering them each year I’ll be flirting with too much danger. I suppose they’re still my best bet despite concerns.

I suppose it may change but 10 feet sounds good at the moment. I know this would take a ladder and maybe I’m underestimating the pain of the trim and cleanup but I’m also telling myself it’s just one afternoon once a year. I imagine the narrower I can keep it the easier that top trimming will be, not too many photos online that show side profiles of large skip laurel hedges so I can see how narrow people have been able to maintain them. I know emerald green does away with this yearly sheering concern and is plenty hardy for my zone, so that dilemma is still there.

A hedge 90’ and 10’ tall with two sides is going to take a lot more than an afternoon to trim. Speaking from experience, I would bid a job like that for about 20 man-hours.

Iochroma- I think maybe 10 feet is excessive and would be some years off anyway to fill out at that height so maybe I aim for 8. I don’t want to annoy anyone with more info but here is a picture of the area with maybe a plan that would reduce the hedge length considerably.

Maybe my distinction between hedged laurels in red and non hedge laurels in green is dumb but I figured maybe because the green area is in shade and amongst tree roots it wouldn’t grow as quickly to keep form with the red area but then again one day it should reach the hedge size and need to be incorporated. By the way that red shrub interrupting my fence will be getting cut back and I’ll be installing fencing there.