I knocked up a very rough mockup yesterday afternoon which will allow me to check some clearances, decide if the deck to deck heights will look and work ok, and make a final decision on what height to mount the decks at. It's one thing to mark a pencil line on the wall, but having a three dimensional mockup that I can place actual models on definitely gives a slightly different perspective.
I had initially decided on the top deck surface being about 155cm from the floor, as I wanted the majority of the layout to be not too far below eye level as this tends to gives a more realistic view of the actual trains. There will be around a 10.5cm drop from the top layer, around the room to the opposite side of the room, and then around an 8.5cm drop as it comes back around to the lower deck again. This will mean a top to bottom rail level height of around 19.0cm from the top to bottom deck, and should put the opposite side of the room deck at around 144.5cm from the floor.
However after placing the mockup against the wall, I am wondering if the 155cm heigh of the top deck may be just a little bit too high? It certainly puts the trains at eye level, and will mean the lower and opposite decks will be at a good height, however I am wondering if the dead side on view will cause any problems with clearly seeing trains on the track closest to the wall when shunting, or even being able to clearly see that the points are set correctly.
I've taken a couple of pics that show the crude mockup, taken from an angle that would allow slightly better viewing of the top level, with the trains sitting on what would be the bottom level. This would place the top deck at around 148-150cm from the floor, slightly lower than my theoretical optimum height.
My tendency at the moment is to proceed with the slightly higher level for now, and if it proves to be a little impractical, I can either make some small steps to stand on if vision is temporarily blocked, or, I can adjust the height after it's all mounted by remounting the wall brackets. The second option is not really the way I'd prefer to go though as drilling more holes in my freshly painted walls in not too appealing!
Alternatively I could try to design a way to allow me to mount the wall brackets set to the lower height, and if I find it's too low I could add spacers to lift the decks. Once again possible, but not the way I'd like to go.
In any case, hopefully this weekend will see at least some of the modules made and mounted to the wall to make sure the levels all work out like they have on paper and that I can actually fit what I have theorised will fit.