The attached thumbnails are the results of my first LF processing session yesterday. Obviously I screwed something up. I've processed B&W film before (35mm) and--I must be lucky--haven't produced such crap.

My workflow was:
1) Kodak TriX 320 shot at 320
2)Negs loaded into CombiPlan tank in Harrison tent. Lid applied in the tent. Caps were on the lid. 4 sheets in the tank. 2 sheets stuck together but appear the same, suggesting they developed equally.
3) Ilford DD-X developer for 7min 20 secs at 20 degrees, based on data from the Massive Dev Chart. Total volume in the tank = 1050 ml. 1+4 dilution as per Massive Dev chart and the Ilford data sheet.
4) Inversion agitation. The negs were in the soup longer than 7:20 because I underestimated the time it would take to empty the tank.
5) Stop bath with Ilford product as per its instructions. Fixed with Ilford product, wash with water for 8 minutes.
6) I was consistent. I did not shorten any of the other steps once I realized it was taking longer than expected to drain the tank.
7) The edges of the film are clear. I can read the Kodak product identification.

The negs are almost 100% transparent! I haven't done anything to the scans other than re-size for the web. They both appear horribly "underexposed," yet I'm pretty certain I set the exposure correctly when making the pictures. The first is my son sitting on a couch, the second is his sister annoying him on the couch. The couch is the giant dark blob (actually green) in the background.

Confounding variables:
1) First time using this camera. At first I was concerned about light leak etc but now that I see the scans I don't think that's an issue.
2) I "guessed at" the development time for this combo of film and developer since the data sheets for the developer don't address TriX at 320, only 200 or I split the difference.
3) I did not pre-soak. The data sheets for the film and developer did not call for it.
4) All the chemicals were fresh from the original bottles.

I'd appreciate any trouble- shooting help people can share. My first reaction was that it the film was over or underdeveloped. Now I'm wondering if I fouled up the initial exposure (I used a light meter and everything...honest )

Thank you in advance for sharing your wisdom