Correctly forming a batch requet inthe web api

I am trying to form a batch request to get multiple preformance information from TXN/Performances/Prices?performancesIds. The docs here https://tickets.wethecurious.io/Test/TessituraService/Batching are fairly sparse and incomplete. When forming a batch request like this. I routinely get the error.

{
    "Requests": 
    [
     {

        "HttpMethod": "GET",
        "Id": 1,
        "Uri": "{{url}}TXN/Performances/Prices?performancesIds=13",
        "ContinueOnError": false
     }
    ]
}