Joe,
Your willingness to use a local steel fabricator makes post bottoms a small bucks breeze. See the guild project in 2003 at the Vermont School Barn raising and visit their site too. You will find barn red hinges on the post bottoms. The hinge leaf fixed to the concrete pier is bolted down with the bolts imbedded in the concrete. The upper leaf is lagged to the post bottom with some bitchithane rubber between the hinge and the post. There is a 3/8" or so lip around this upper leaf which mates with the other when the hinge is closed. After the frame is true here comes the welder to permanently join the hinge leaves together. Don't and won't move in any direction . The bolts & lags are 3/4" stock if I remember correctly. The pier top, the hinge, the post bottoms are well above any water/snow line.
You set up , insert the 3/8" hinge pins and push/pull the wall/bent up. If you search the pictures about the project, including the Mountain School website,you will find these bright red goodies in various levels of detail.
If memory serves me correctly Ed Levin was the responsible design engineer on these.
