y dnt u take out tht big rectangle at the top and put in a banner instead...sure the rectangle gives more CTR, but the other way around would be more pleasing to a net user...and ur nt posting to a niche topic? would be better the blog was more concentrated on one topic
My tried and true experience is: One 336x280 rectangle, top left, above the fold, with the content wrapped around and down the right side of the rectangle, to blend the ads into the background of the content. No other ad boxes, as you want the best ads served at all times. Sometimes less is more....