This has been a very interesting subject, even if it has strayed far from the original query. Having viewed it up to now as a guest, I just joined RMWeb so I could make a small contribution.
My strong impression is that track plans were rarely elegant on the real thing - especially at places where the station had been substantially expanded to cope with additional traffic. Some, like Euston, were a complete mess. It was rare to have the opportunity to completely remodel a station's trackwork in the steam era. Many were modified in a fairly higgledy-piggledy way.
St Enoch was effectively 2 stations side by side, so could be reduced by a third or so for modelling purposes without losing the atmosphere of the original. It would still be very large though. The northern-most 2 platforms (platforms 1 and 2) would make an interesting model in themselves. They appear to have been designed for 2 trains to use each platform without impeding each other - a feature rarely modelled. Here is an extract of the signal and track plan from around 1900.
Whilst large termini are exciting to contemplate, they require a huge amount of effort to operate - far more in the realm of a group than an individual - especially in the steam era, when there would be lots of light engine movements on top of the service itself. Even platforms one and two on their own would require a lot of concentrated effort to work realistically.