I've run wix and some other variety I got from NAPA. I prefer the NAPA ones only because they're slightly smaller and easier to stuff in the frame.

X whatever on the fuel clamps. It strikes me that in an unpressurized system, if there's a leak it's not a problem with clamping force but unserviceable hoses that are cracking. Even then, the only time I discover a leak on an old hose is when I've disturbed it. That said, hoses are the first thing that comes off and gets replaced in my garage. If you're cleaning a carb and don't have filters, you're kinda lying to yourself.