Overall, I like the mod! I have hotkey-related feedback as well, including expanding upon DranKof's suggestion:
These inserters are currently up to a 4-step process:
1. Select output tile (initial placement / R)
2. Select input tile (SHIFT+R)
3. Select output sub-tile distance (SHIFT+N)
4. Select output sub-tile angle (SHIFT+F)
I like your hotkeys-only approach because it progresses from most common activity to least common, with the ability to skip later steps when you don't need them, without needing to open or close some UI. Much of Factorio is designed this way currently, so it feels consistent and fast.
Suggestion #1:
Make the first step the selection of input tile, both for logical flow (thinking about input before output), and so that a freshly placed inserter won't immediately grab from someplace the user didn't want it to. This suggestion is highly debatable and not a must for me.
Suggestion #2:
Don't use SHIFT+N as a default key combo. SHIFT+N is not a left-hand key combination, meaning the user has to let go of the mouse to use it while still hovering the target inserter -- not very user-friendly. Some people with big hands might be able to do it left-handed, but small-handed people, injured people, and people with ergonomic keyboards (me) can't pull it off.
Suggestion #3 (this is DranKof's suggestion):
Don't break sub-tile positioning into two steps. If it's just one step, you only need one hotkey to cycle through the options. This would conveniently let you replace SHIFT+N and SHIFT+F with CTRL+R, keeping all manipulations on the R key by default.
The overall process now looks like this with all my suggestions:
1. Select input tile (initial placement / R)
2. Select output tile (SHIFT+R)
3. Select output sub-tile position (CTRL+R)
Suggestion #4:
Sub-tile positions could be selected by rotating clockwise through:
Default (Far-Middle)
Far-Right
Near-Right
Near-Left
Far-Left
Note that I left out near-middle (which is possible in the current version of the mod). I don't think that position is useful, though I could be wrong. Since position selection is a cycle, minimizing the number of options is key to making it work without being frustrating.
Suggestion #5:
You could eliminate far-middle position as well. Its only useful, fuctional value is in maintaining un-modded and legacy modded behavior. (Though aesthetically, it does look nice to have a straight arrow in the defualt case, which could be a big deal for all the OCD people out there. There are visual solutions for this, if necessary.)
You could compromise here to avoid breaking un-modded and legacy factories by still supporting the far-middle position internally, and just remove the ability to create any new inserters which use it (except via old/shared blueprints), and don't include it in the hotkey rotation. The default, freshly-constructed position could then be far-left or far-right, your choice.
I like removal of the middle positions because it clears up ambiguity about what the inserter will do with regard to belts.
