I'm building a bookcase with adjustable shelves with a 46" span that
will likely carry some heavy books.

To cover the load, I am making the shelves 1.5" thick (double 3/4"
plywood).

I now want to make sure that the shelf pin setup I am using is as
strong as possible.

- Can I assume that all other things being equal, 1/4" pins will support
a heavier load than 5mm pins (since the diameter is larger)?

- Will using a "sleeve" in the shelf pin hole add strength and prevent
tearout from too heavy a load?

- Would adding a third parallel column of pins on each side support
*materially* improve the strength?

- Any other suggestions to maximize strength of a shelf pin setup?
(note: I would prefer not to add any intermediate supports)

- Finally, any feedback on the Rockler Shelving Jig? (it seems to do
the job, comes with self-centering bits, and is affordable)