I would strongly urge you to look at O-31 if you can fit it which will let you run just about all traditionally size equipment and make use of the more refined O22 tubular switches. There is even O-31 Fastrack and switches should you want to go that route.
As with any track and equipment, you must look at the minimum curve specifications and ensure that it is smaller or equal to your smallest curve size on a given route.
As for other track choices beyond O-27 tubular, that can get you the small tight curves, you can look at using something like Gargraves flex track. Be warned that shaping the flex track, especially tightly, can be "an experience". People have built jigs to help them make the bends.
