I want to attach two 4" long, 1.5" dowels to the fascia board. The free
end of each dowel will hold a Y Screw Hook like this:
http://hardware.hardwarestore.com/28...ok-506281.aspx

The two dowels will be 13" apart, so I can place my aluminum extension
ladder between the two hooks to prevent side-side motion. Without
extending the hooks away from the fascia, the ladder will press against
the 1.5" overhang of the first row of (brand new) shingles.

I am aware of hanger hooks like this:
http://monsterfastener.com/sizelist....lt&icstyl=Wood

But I'm not sure how to use them, especially with machine screw threads
on one end.

Another factor which may or may not be a problem: the fascia board is
off-vertical by 18 degrees, the pitch of the ranch house roof.

I welcome your suggestions for other approaches.

R1