My first post! I'm starting a 10'x12' platform for a play house/deck in two trees. The available 1"+ TABs and brackets seemed overkill for my application, so I went with 8" x 3/4" stainless lags, and fabricated brackets from "c" channel and steel plate. The brackets go below four supports of 2"x12"x12' treated lumber and will hold up a 'box' of 2"x6"x10' for the house and deck. I'm going to post the finished brackets here. The 1/4" plate and channel are arc welded together. Pictured are the 304 stainless lags with stainless washers and an aluminum pipe for a spacer. The brackets are now installed, and I went with a 3/4 i.d. galvanized pipe as a spacer for the installation but they didn't make it to the picture. I used a new 1/2" auger for the pilot. It took a leverage bar to get the lags secured in place. After clearing the bark at the supports, I used a stack of the stainless washers as a spacer to get the bracket beyond the bark that remains. It's still in progress so I'll keep posting as I go.