There is a POL version of world forge that is really cool, better than the UOX version.
I forgot all the improvements it has, but for one thing, it doesn't go by block, it goes by tile, so you can freeze/melt exact areas.
There are some other cool features like the fact that, since it's POL, it also comes with some command scripts for freezing items, so you can actually freeze the items in-game using a special set of commands and it's much easier to get things right.
Also, I'm pretty sure there is no "no use" area in POL
Might be worth checking out if you can't avoid that problem. I love POL for world building since it's potentially compatable with every other tool AND being able to make your own commands is so usefull.