Make sure your skin is well hydrated and properly exfoliated so the dry bits won't show up. Wear a primer underneath to create a smooth surface to apply your foundation as well.
I don't think sponges are unhygienic, if you want a sheerer application of a foundation like Full Coverage, dampen your sponge, remove all excess fluid and apply your foundation by not putting too much product on your sponge and layering it on areas that you would need more coverage.
If you like sponges but still feel they're unsanitary, you can buy inexpensive wedges. A good sponge can also be washed, Make Up For Ever's Ellipse Sponge is a dream per example.
As for the brush to apply it with, use the 190 when you want a more sophisticated polished look or the 188 for a more soft and sheerer application, I think the 188 is too small and makes it a longer process and would prefer the 187. But I apply my foundation with the 190 and it I can apply it sheerly and still give it that airbrushed look.