Late to the party here, but I am a "belt & suspenders" kind of guy who over builds everything. Went with 16 gauge, 1/2" x 1/2". Spent about 2x's more, but could not find any 19 gauge that wasn't a rust bucket from China out of the box...
Fencer Wire- 1x1, 1/2x1/2, black. They also have 14 ga...