So, following our other discussion in the Feature Request (which, by all means, disregard if there's meant to be a tool for this), I hunted down and decided to try out the Smart Link tool you mentioned. I found it in my Shortcuts Bar, which was missing a translation key and appeared as "Unknown key: "shortcut-name.smart-link-tool".

After enabling and selecting that tool, I had a selection box that appeared to do nothing but draw a green rectangle over whatever I designated with or without any additional modifier keys. Although, holding Alt and then trying to select will unselect the tool I suppose.

After that I looked in my Hotkeys and discovered that Alt + Shift + Click should summon the tool as well, and as soon as I did that and clicked anywhere I received an immediate error as follows.

__Kux-SmartLinkedChests__/modules/Chest.lua:263: attempt to index local 'chest' (a nil value)
stack traceback:
    __Kux-SmartLinkedChests__/control.lua:33: in function '__index'
    __Kux-SmartLinkedChests__/modules/Chest.lua:263: in function 'getFilterFromChest'
    __Kux-SmartLinkedChests__/modules/FilterFromSource.lua:124: in function 'endAdd'
    __Kux-SmartLinkedChests__/modules/FilterFromSource.lua:108: in function 'set'
    __Kux-SmartLinkedChests__/control.lua:30: in function <__Kux-SmartLinkedChests__/control.lua:29>
    [C]: in function 'xpcall'
    __Kux-SmartLinkedChests__/control.lua:29: in function 'fnc'
    __Kux-CoreLib__/lib/EventDistributor.lua:165: in function <__Kux-CoreLib__/lib/EventDistributor.lua:160>
----------------------------------------
Kux-SmartLinkedChests v2.0.14
Kux-CoreLib v2.11.0
----------------------------------------
Steps to reproduce:
...describe which steps you have done before...

I then repeated these steps in a completely vanilla game including only Smart Linked Chests and its dependencies and got the same. I suspected it might be down to the specific chest I was using (Surface Linked) or not having other things placed or a variety of other things, but it seems to be the same no matter what I do or don't have in the game, even on a completely new and vanilla game immediately after the rocket crash.

a) missing translation fixed
b) Alt + Shift + Click is not the SmartLink Tool, it is a pasting tool, but i have fixed the error, it occurred when no chest was selected
Fixes are available in next version

Usage of smart link tool:
- select the tool from shortcut bar
- pull the rectangular area over the assembling-machine the inserters and the chests
see https://prnt.sc/Vo-dnX2swwyD
then the chests will be configured
Note: Sufficient chests must be selected and all inserters must be configured correctly

General info: All selected chests with a valid inserter configuration will be configured, so that you can also select multiple assembling machines and chests simultaneous. The inserters ensure the correct assignment between chest and the other object which can be a smart linked chest or an assembling machine.

Oho, I hadn't considered the Inserters. Thank you very much. I'm sure you must be getting sick of half the discussions around here being from me. This is for sure one of my favorite mods.

I think I hadn't considered the inserters part of the equation because you use the flat ones so I didn't even realize they were present. That makes sense though. Now that I've tested it this does exactly what I was hoping it would.

Edit: Oh my god, this is just the nicest thing ever. I wish I'd realized this was a thing ages ago. I've been ignoring that tool forever, but I just set up a new factory with like 12 new products in a fraction of the time.

I wish I'd realized this was a thing ages ago

it hasn't been around for that long. ;-) So you didn't miss out.

but I just set up a new factory with like 12 new products in a fraction of the time.

yes, that's what it's for ;-)

Keep on having fun with it. but remember it's just an experimental mod i'm still working on.