All kinds of good possibilities. For longevity it seems like galvanized or stainless steel hog rings with screws and fender washers on the tube frame might work out. Stainless can rust if it comes in contact with carbon steel. I used stainless steel j clips on my brooder cage. Klubertanz has...
J clips would be too small for 8 gauge wire. Hog rings might come in a bigger size but I haven't used them. What about just using a roll of galvanized wire?