Bare root hedging

Hi.

I'm new to having a large garden. It's just been redone as has lovely new grass but absolutely no privacy and we are right next to a public foot way. The only thing we have is a 3ft tall wall.

Anyway, I've been looking into bare root hedging and have ordered 250 plants of a native mix. I've been preparing my garden, I've come 70cm out from the wall then have measured out a tench 60cm wide as I plan to do a double row, does that sound about right? I'm doing double row at the front and single towards the back. I'm just worried about the hedges taking up a lot of my garden but I'm assuming if we keep it trimmed back we should be ok?