Survey incentives

Not sure if UX is the right place for this, but it is partly a behavioral economics question so I hope I'm in a reasonable place.

For a survey prize draw, has there been any research done to assess whether, everything else being equal, a better response will be achieved with either a small number of high-value prizes, or a larger number of lower-value incentives? For example, if I have a £150 research budget, does it make more sense for me to offer than as

• 1 of 5 £30 Amazon vouchers
• 1 of 3 £50 Amazon vouchers