Here is something to think about. The rule that a reversing section must be
longer than your longest train isn't just a good idea - it's a "rule". There is a
caveat to that rule that goes "... there are times when you might run a train
longer than your reversing section and it will work and you will be tempted
to ask "what's the big deal?".
If the train bridges both ends of the reversing section - at the same time - it
will create an electrical problem that your auto reversers do not know how to
deal with - it is possible that the train will "stutter its way past the problem"
but that looks really ugly. It is best to avoid it.
IF your layout is so small that your auto reversing section doesn't work
right - then the correct/first response is to cut down the length of your longest
train(s). In other words - avoid the problem. Yes, I know, I want to run
long trains also ... but not so long that they are longer than my reversing
section, staging (storage) tracks, or my shortest passing siding. Well, OK
I agree that doing a saw by is fun and you can avoid it by not having two
trains that need to pass arriving at that siding at the same time. But even
the real RRs considered doing saw bys a problem and avoided them if
possible. So should we.
The physical layout (such as the length of storage tracks, passing
sidings, and reversing sections) is best treated as a "given" and then
you adapt to it.
Here's a last consideration - if you ever intend to have more than one
operator on the layout at the same time ... then if you assume that
person is not super smart and can not learn complicated stuff EASILY
(such as saw bys) then the layout will run ... wait for it ... better for YOU.
For example, let's just think about having the other operator being your
6 year old grand.