I ended up creating a string of numbers surrounded by ';'. It looks like this
;123;;456;;789;
They are passed to the SPROC as NIDList
The SPROC looks like this
Code:
	@NIDList VARCHAR(MAX)
AS
BEGIN
	SET NOCOUNT ON;
	SELECT [NID]
		  ,[P1]
		  ,[P2]
		  ,[RC]
		  ,[Active]
		  ,[Flags]
		  ,[Hist]
	  FROM [SectNum] 
	  WHERE @NIDList like '%;'+cast([NID] as VARCHAR(MAX))+';%';
There are approximately 50,000 records in the table and if I retrieve 300 it takes a couple of seconds. Not great but acceptable.