I would get the new water pump. It will save you the time and effort of having to do it again when the rebuild kit does not work. It is a lot of work to remove an old pump and replace it. The labor alone is enough to suggest a new pump. You might want to get the radiator boiled out while you have the pump off. You also want to get a new bottom hose and clamps.
Check the oil level for the touch control. Sometimes being low on oil can cause erratic response. The touch control should function totally independent of the auxiliary valve and should generally reflect the location of the control lever just like on the SC. When we would remove the 2-point on our 200 (for the corn picker) we would remove the auxiliary valve control lever. We also would close off the hoses with pipe plugs. It did not affect the touch control which raised and lowered the corn head.