As with any masonary application all of the above works, I like to use the morter joints to install my tapcons or molllys. It is alot easier on the drill and doesnt affect the rigidity of the block. A ramset is a great tool for basement framing and sill installation, but whoever said it is too much power is exactly right, especailly for this application. A 1x4 is a great fur but those 1 1/4 inch nails are hard on the fingers and the thumb. lol
On a side note a funny story about siding on cement---- An old man I know used to work for me and anytime a new construction job required flush wall angles on a non furred concrete foundation he would, drill his 3/16 hole and put a twig or small branch in the hole and break it off. Then he would use a roofing nail and hang the panel as usual. I am still leary of looking that way when i drive by those jobs, because the wind here in the midwest is less than pleasant in January and February.