Hey, its great mod but I do not like constant gui element. Could you link it to vanilla floor size? or at least hide it when you do not have any belt in hand.
Great would be to show places where the items will be placed, just simple thing like colored field (like floors).
Other idea is to add other items, like underground belt, pipes or even assemblers (if size don't matter).
If you could add some logic, like 2(4/2) (4 belts 2 free space and another 4 belts) it would be great too. And then (with other items) it could be useful more, for example x(1/2) -inserter 2x free space inserter.

3rd and 4th idea may be too complicated and overpowered (and close to blueprints), but 1st and 2nd would make mod much better.

I don't understand what you mean by vanilla floor size, but I think auto hiding should be possible. also underground belts should be doable too, I'm going away for three weeks sadly, so the underground belt one will probably not be out soon, the version with GUI hiding should be out before Saturday evening I think.

As for the second two, I do indeed think that would be a bit too overpowered. Use blueprints for that:)

By the size of floor size I mean size in what are floors built (1x1, 2x2... increased with "+" and decreased with "-") and then there are green (?) field that shows where it will place it.

Yes it would be overpowered, but wouldn't be that great for early furnaces setups? ;)

I could do that, but that would require a lot more work. Don't know yet