I don't find them to be excessively thicker than stock. The rear backstrap is kind of a middle ground between the stock straight and arched. I think you would find them thinner than Hogues. For me I also like the added finger grooves.
They are a little thicker than the factory plastic but they make it a somewhat rounder grip than the squarer factory grips. Not a huge change. If the factory grips are not at the absolute size limit for your hands you're probably okay.