More top soil

Hi guys, we have been very busy rearranging the veg plot, work is in full swing but I need your advice.

The old paths and boarders have been lifted and are waiting to be put in their new positions. This is leaving lots of holes/rows about 6" deep. Now to fill the spaces. I have not dug over all of the plot yet and a few weeds need to be lifted. We are digging a very big hole about 1m 80cm deep so as you can see lots of surplus soil will be on hand. I am not sure about two things.

Firstly should I dig over the whole plot then add the soil. We are looking at using a lot of the soil to level the area and raise it. We probablly want to raise the whole area by about 5"to 8"

Secondly how much of the soil can I use. So far its of varying quality but at a foot deep looks OK. Is it a case of it is looks useable go with it or don't use after digging so far down due to quality.

After all I want fantastic veg. I am able to mix manure in where suiltable so can improve the structure some what.

Any comments are very welcome.

I think this will be better off in GYO, than "Chatting", so hang on ......