Built up ribs are now commonplace on many Chinese ARFS--
strength to weight is better but the real reason is that they can use firm balsa and thru laser cutting processes used, make best use of material.
The use of latest manufacturing equipment allows some bold iprovements over the more commonly used structures.
At lower costs and with better accuracy.
many ofthese rib structures are simple notched upper /lower pieces and verticals which fit --others are dove tailed .
the structure you select will make a huge difference in the strength to weight you can acheive.