Ok, finally figured out the parameters are not local indices on the account you specify, but global operation indices. However, I'm still seeing odd results:
{"id":4,"method":"call","params":[2,"get_account_history",["1.2.29495","1.11.88751",10,"1.11.96290"]]}
leads to returning op ids 88893, 88846 and 88845, but this following call, which has been tuned to return only those results by exact index range:
{"id":4,"method":"call","params":[2,"get_account_history",["1.2.29495","1.11.88845",10,"1.11.88893"]]}
leads to nothing being returned at all?