I don't know the exact size of the shims as I haven't done em yet, But work out what thickness you need before ordering any.You probably know that already.
I usually buy a complete kit when it is time to change the belt.
Gates part No. for the 1KZ-TE kit is VKMA91022 this will include a tensioner and idler if there is one. It does not contain seals.
I prefer Gates over DAYCO as that brand seems inferior in quality and has let me down at crucial times.