Dear Colin,
fom an "Operation" point-of-view,
- coupling/uncoupling,
- setting brakes or sprags,
- and turnout maniplulation,
are actually around 70% of the "time" taken on a given shunting job.
(as judged by doing an anedotal "time and motion" study of various switching missions)
What is interesting is that we, as modellers, tend to
- do hands-off couple/uncoupling systems
- use turnout motors
- and ignore "the setting of brakes" altogether
Now given, in sub 2' gauge industrial railroading,
all of the above tasks are performed <manually> in the prototype,
and cannot be easily <manually> replicated in sub O-scale (1:43 - 1:48).

However, forcing,
(oops, sorry, "encouraging"),
the model operator to <wait> between moves,
(IE actually STOP for 2 realtime seconds worth of "scale time" for the scale driver to
- stop his Lister + train
- get off the loco
- walk to the turnout
- change it using whatever manual control is in use
- walk back to the loco
- remount,
and <then> set off in the reverse direction)
instead of simply "flipping the reversing switch, and changing direction",
can materially Improve the "feel of operating a railway",
(as opposed to "running trains back n forth")
Said another way, we tend to focus on the "driving of the loco",
and use various modelling techniques/solutions to mitigate or eliminate entirely the "brakeman"/"shunter"/"guard" parts of the job we call "shunting" or "switching".
That's fine in smaller scales,
(where modelling "Industrial style coupling systems" dang hard

)
or where the 12"/1' scale modeller's focus <is> on "running the loco",
(and they don't want to think about anything else

)
Indeed, for a layout specifically intended for "show Inglenook operation",
where mechanical reliability and "hand's off shunting" while in the hands of "any un-trained punter who accepts the offer of the throttle"

,
are high on the list of "must haves"
I <would> reccomend Kadees or equivalent
However, on small, nay Micro layouts such as the Simplicity Sidings,
who's operation is in the realm of the hardcore sub 2' gauge industrial modeller,
(IE these are the people who <would care> if a wagon is left sitting on a spur un-spragged),
re-introducing the physical tasks integral to doing actual 12"/1' scale shunting, beyond simply "driving the loco",
(even if they are just represented by waiting between throttle and reversing switch operations

),
can give much more "operational value"
(some might say "play value")
out of a simple "2 spurs and a headshunt" track arrangement than the 1st, 2nd, or even 30th glance would seem to indicate...
(Consider giving each car spot on each spur a specific number and duty, thus adding another layer of "purposeful meaning" to each shunting move,
beyond simply "moving a car because it's there"...)
Now, where things get interesting is that with Gn15,
things like 3-link or single-link couplings <are> totally "do-able",
without requiring the operator to wear hyper-macro-zoom-trifocal lense specs,
(as compared to doing 3-links in sub O-scale, ask me how I know this!

)
A small tool, using a length of 1/2" dowel as a handle,
and a short Z bent piece of 0.040"brass wire mounted in one end,
can easily reach between Gn15 cars,
and allow simple "hook and drop over a pin" manipulation of 3-link couplings...
I'll apologise if this sounds like a rant,
but Colin, for someone with your level of "Hands On" industrial modelling and prototype knowledge,
I suspect that using scale 3-links or similar <may be> "the most appropriate solution" for the layout size, purpose, and owner/operator preferences...
Sincerely Hope this Helps...