Thanks for the quick update!
It's okay to leave out close lane option. I am not using this feature much anyway.
The mod development is fine for the moment. But thanks for the offer! I will contact you when needing the help. :D
Found a minor problem when changing longer inserters but not using max range.
Steps to reproduce:
1. Place vanilla long-handed inserter.
2. On the long-handed inserter GUI, select range-1 diagonal input and output tiles, and accept changes. As below figure:
3. Reopen the GUI, the display of output tile is shifted outward, as range-2. (Actual output tile is still the correct range-1 diagonal tile.) As shown below:
I made some range-3 and range-4 inserters. They all have the same problem shifted outwards.