To be honest, I am working to the form "described" by Rip in Practical Programming (and Strong Enough). His descriptions of good form, plus the anatomical reasoning behind the movements, makes for a very vivid picture. Basically, I line up the bench, line up the bar, feet planted, ass down, decent arch in the lumbar. As for the shoulder girdle, I am doing two things. Rip describes squeezing the shoulder blades back and together, this has been the key for me. By the time I am ready to take the weight, my arms are almost straight, making the first movement just a locked-arm shift of the bar to the top visual reference point. I have long stopped flaring my elbows (which I used to think "worked my chest better"), and keep them somewhere between neutral and slightly tucked. So far, this has allowed me to bench (albeit with very modest weights) with minimal discomfort.
I didn't unfortunately... I am away that weekend! I made contact with TomC though, and will look to get some coaching/form checks complete once I am through the month of August.