we use H clips,they slip onto the sheets between the rafters, helps support the sheet.
the paper is another line of defence from rain.only thing,the so called self-sealing shingles bond to the tar paper or felt and not to the wood structure.when i did my roof,i used 30 year fiberglass laminated shingles,the edge has a random cut,like cedar shake effect.
it was a hot sunny day,if you didnt place the shingle where you wanted it,grab the putty knife and lift it carefully.those particular shingles stuck like - crazy.
last roof i have to do on my house.
bottom three feet get ice and water shield,a rubber membrane to prevent leakage from ice dams.last winter was bad for it.
progress sounds good,Dan.keep poundin.