Nice web page.....I especially like the little tunes that play :-)
I'm in the process of building a 30 foot long retaining wall with my neighbor, and we can's seem to agree on whether to fill the 8" cinderblock 'holes' with concrete and rebar or not. The footing is 16" wide by 12" deep, with four 1/2" rebar rods imbedded. This footing supports a 4' tall wall that has 8" cinderblocks against the bank faced with standard red brick that matches the neighbor's house. Each block is tied to the footing with the standard 6" footing anchor. I have installed 1" weep holes every 4 blocks. My neighbor thinks filling each hole is overkill. I think it is necessary for the long term structural strength of the wall.