Welcome to TrainBoard. Good to have you on board. Most of us started with small layouts as has many model rails before us. We've all learned that it is better to maximize the radius of your curves. Eventually you will have room for a larger layout and you will be able to see your pride of the rails, the Big Boy, operate on your rails and look good doing it. Have fun!
I've run it for about two hours so far, and it has performed admirably. We even tried running it in reverse around a few times, and it tracked perfectly without a derailment. I haven't even tried our passing siding on the one end, which is 8.75" radius. Not even the Kato Mike likes that terribly much. Our one turn, which is about 13.5" radius it looks splendid on. The remote is a bit finicky to control speed and direction with, but I use it only to operate the sound effects, speed and direction are controlled by the DC power pack.
On the prototype a road's biggest engines were often barred from using some sidings because of tight curves and clearances, the real Big Boys didn't roam freely over the whole Union Pacific either. The whole layout doesn't have to accommodate your biggest engineif you're tight on space to fit in a spur here and there.
Congrats! I have a similar situation with my layout too, it's coming out to be a dogbone shape, so mostly straight running, but the loops at either end incorporate 11" radius curves since for me it was either that or 19", and 19" did not fit. I was hesitating to get the GS-4, but now that I see that your Big Boy works out, I think I'll go ahead and pick up the GS-4. My strategy for layout design comes with putting in a lot of straight line run, at the expense of tighter curves on the turnaround. I dont have much space in my apartment, so the dogbone works out nicely in letting me run longer trains. Another thing that I do once in awhile (mostly around christmas) is set up a long loop of unitrack on the ground, which allows me to run very long trains just for fun.
