Here we go mate, mine is 2m, the rear being as far back as possible without fouling the rear door, so a 2.5m job would be about level with the front of the door mirror, which is a long bit of unsupported over hang and I have my rails a far apart as possible......
I have a cheapy flat rack but I only fit it when on the road, its a pain for just running around the place empty as a bit of wind noise, have cut most out and another mod should do it.....
Front of awning..
Rear view gives about 20mm clearance
Rack mount with bugs....