I am about to start construction on "U" type or "C" type spars. The top of the spar is 1 1/4" x 3/4" Sitka. The bottom of the spar is 3/4" x 3/4" Sitka. I've been reading on the web that the strongest web is 45 degree grain to the spar. I plan on using 1/8" baltic birch and cutting the 5' x 5' sheet diagnally to acheive the 45 degree grain and scarffing the ply to get the length I need. Now the question - grain orientation, should the grain run from the bottom of the spar upwards toward the root (fuselage) to the top of the spar? This is a high wing basic ultralight 2 seat side by side aircraft with front and rear spars and front and rear struts. Any input will be appreciated.