Hi Shawn,
We've had quite a lot of success with tomatoees over the last couple of years so I'll just describe what we did:
Our soil is also quit clayie (is that a word?). Dug & forked the ground 1 spade deep and turned in 50% cow manure and left it to soak in through the rainy season. Turned over the ground again before planting. Planted the tomato seeds directly into the ground at about 18-24" intervals (2 rows 25 ft long - along a south facing wall) and screened to 3ft height with 50% screening material (This also kept the chickens & dogs out). We planted Basil between the tomato plants as it's supposed to reduce pests - which seemed to work. Be careful not to over-water them (causes wilt and brown leaf edge). Little or no crop from about 4 plants but we cropped over 5kg per plant from the rest. Hope this helps and good luck!