Get a good helper
I used a similar tungsten bar on my taildragger. I got an experienced riveter to buck while I had one hand on the gun and one on the set to make sure it stayed put...couldn?t have done it otherwise. Set the gun pressure around 40, did a couple of light hits to make absolutely sure we were both on it, and then quick burst to get them set. I think these were the toughest ones of all to do.