Dip Switch settings for furnace circuit board
You are correct -- turning S7-1 and S7-2 both off will disable the second stage of heat on your furnace unless it's called for explicitly by turning the furnace's W2 input ON.

Since you have a single stage thermostat, the first setting I'd try is Auto -- i.e. S7-2 ON and S7-1 OFF.  That lets the furnace control board make a choice on its own regarding how long to wait before kicking the second stage of heat on.