" have some 1.25" thick clean oak wood"
yes with a "maybe" ...white oak is fine because it has closed grain, red oak is open grain and is not suitable for outdoor use (unless you carefully seal the outside surfaces) ...any cracks later will wick into the center ...exclude all knots since they are hard and screw up shaping and sanding and tend to crack out
you can economize on wood consumption for tapered planform if you plan ahead for glueing.
the following is a two part tutorial posted a long time ago on my construction techniques:
http://www.greenpowertalk.org/showthread.php?t=1188
http://www.greenpowertalk.org/showthread.php?t=1190
note the use above of trailing edge strip with grain parallel for that thin trailing edge
If you followed Dan Lenox's recent thread on glue, I am in full agreement with him on technique ...use your planks 1.25" edgewise and make them as thick as you need 1.5" or 2" (mine were 2.5")....use Titebond III liberally and forget the two or three parts expensive epoxy glues ..not necessary ...I bought a gallon for $28 and used on outdoors oak deck stairs and they have been perfect going on 4 years already
Stew Corman from sunny Endicott