"Is it correct to say that if shear webs are good, then more & sturdier ones are better? "

I would say the answer is no, remember weight is an important part of aerodynamics. I am no expert on kits, since I am in the process of building my first one as well. However, with my wing it called for the same construction as what you are descibing. With just the Ribs, Spars and Shear webs things still seemed a little flimsy, but once I started putting the balsa sheeting on things firmed up nicely.

Hope that helps.

Rick