Waterblocks are pretty heavy for thermal tape and a thermal adhesive/epoxy is a permanent option, and as such it would be my last option.
You should be able to buy some small eyehook bolts, see images below, and either bend the eye open or cut it open. And then you need to make a strap out of a piece of "hard" plastic or a "stiff" piece of metal.
You should be able to buy some small eyehook bolts, see images below, and either bend the eye open or cut it open. And then you need to make a strap out of a piece of "hard" plastic or a "stiff" piece of metal.