Thanks for the input.

I'm looking at worm-drive clamps from Gates (they should know how to clamp a hose, right?). These for silicone have a smooth inner band to protect the soft hose; is there any reason they couldn't be used on rubber? They also have the perforated version for firm rubber. They're both about the same price at two or three times the store brands, but leaks are annoying enough to justify it.

The heat-shrink clamps are interesting, but they're single-use and look like it would be hard to remove them without damaging the hose.