Nailing is worse. Thr hole is not a hole, just a divet where to make the hole.

 

I understand it's a mark where the hole goes. My point was a screw gets wider the farther from the tip so if you start it slightly crooked or a knot in the wood below causes it to pass through the hole at an angle it would do what screws do and wedge it's way in under power. A straight nail smaller than the drilled hole wouldn't wedge in the hole and would take a mis-strike from the hammer or a knot hard enough to deflect it to damage the tile.

That's just what I'm visualizing, not some kind of correction. You're the one who knows what you're doing, I'm just trying to get an idea of how it works.

Thanks Nat.

 Frosty The Lucky.

 

And here it is

 

URL=https://lunapic.com][/URL]
 

 

 

 

And the jig that was used 

 

 

Looks solid from here Nat. 

Frosty The Lucky.

It's done , couple of shenenings need to be added but that's detail, like sheet metal on one side.

Nice work.

Thanks  it was fun project 

View from top on new roof compared to old one on left