I have no experience using a spinlock in this application. I've sailed a couple of beach cats that used them for the main sheet cleat - and didn't think it offered any advantage over a conventional cleat.

The disadvantages I see in a traveller application:

- Bulkier
- Less reliable - I've had a couple of spinlocks blow up - but never a cam cleat
- More expensive

I'd stick with a cam cleat.

Chris.