It is usually reommended to stay with the factory temp thermostat because if you change the temp of the engine you change the way it wears.
Running a different temp can cause different wear on the internals.
Just my oppinion on it.
Also, you may want to do a good blast flush on the engine after sitting with the CLR in it since it will allow stuff to come loose and fall down in the block and settle in the coolant passages.
If you have an air compressor you can use air and water to flush it.
Take the thermostat out and remove the bottom radiator hose.
Put your air line and water hose together and wrap a wet rag around them and push them tight against the thermostat inlet and let water start filling the block while giving it an occaisonal blast of air along with it (about every 10 seconds) hit the air.
Do this in both directions through the block alternating using the lower hose and the thermostat inlet.
It works really well for blasting the sediments out of the block, because the air pressure builds up behind the water and really forces it through the block fast.
My coolant looked pretty clean when I got my car and I have been cleaning blocks out like this for most of my life.
The first couple of blasts came out yellow with chunks and now the cooling system is nice and clean.