Bed Renovation (More Thrilling Details)

I'm going to fill the gaps at the bottom with 3 by 2 to make sure there is a solid seal between the bed and path. I'll have to dig it out a bit first to fit it in but it should be worth it.
The thing is I'm levelling off the tops of the beds this time instead of going with the flow of the land, so I need to fill in the bottom edge but not the top. The bits of corner standing proud of the planks are to hold on to initially or to screw another board to if I want to raise the beds any higher.
As I see it, the higher they are the less bending down there is. The main obstacle really is the amount of topsoil/manure mix required to fill a bed that size. Still, if I did a few together I could order a couple of tons and be done with it.