Fuel Selector Valve Prep

I countersunk the three #10 screws that hold the fuel selector valve cover on. By disassembling my countersunk cage I utilized the center spindle holding the #10 countersink cutter in my drill. I cut all three by hand. The aluminum cover disc is 0.080” thick, which also happens to be how thick the screw heads are. So to avoid enlarging the holes with the cutter I went slightly less then that. The screw heads sit slightly proud but that won’t be an issue. From there I moved on to flush riveting the three #10 nut plates to the valve body using my hand squeezer. They all came out great. The folks at valve manufacturer Andair in the U.K. recommend securing the small #4 fuel fitting screws by either stagging them or using Loctite 648. I had no idea what stagging meant and had to research it. It means putting a nick in the edge of the screw head that locks it. Hmmm... that’s a new one for me. As for Loctite 648 it’s not the standard blue 242 or red 243 thread locker. According to the Loctite website it’s for bonding cylindrical close fitting parts. I’m unclear why Andair recommended the 648. I couldn’t find it locally and had to order it. My concern is future disassembly if needed. 242 is not a problem. 243 needs heat or impact tools. 648? I’ve no idea. I called Andair to query them. The rep I spoke with didn’t really know why they recommended 648 vs 242 which was unsatisfying. They just normally stag them he said. I’m leaning towards using Loctite 242 since it works and I’m familiar with it. We’ll see. Securing 12 small machine screws shouldn't be this complicated.