Your best option if you have the ability it GTAW, tig/heliarc. Next would be 1/16th 6010, deeper penetration, smaller rod to move it faster. You do not need a gorilla weld, remember the first two digits are tensile strength, 7018 has a 70 ksi tensile strength. Run the smaller rod quickly and then wait until its cool to the touch to put your second pass on if you feel that you want more weld. If I need to make a 3/8" weld to reinforce the C then I need a bigger axle and C's. if you need some rods ill grab some from work and ship a pound to you if I need to. Hell I could send some 309 wire and you can have stainless welds to be different.