Brad,
To be sure, you will ultimately adjust your dimensions, wicking material, etc. as you gain experience with your design. Best bet is to make up a few, then document how they perform with photos and a grow log recording what happens.
As a datapoint, have you read through the EarthTainer Construction Guide? This would give you a perspective on some of the issues I tried to address in SWC design.
http://earthtainer.tomatofest.com/pd...tion-Guide.pdf
Raybo
