the white sauce i usually use is 3/16lb margarine, 1/16lb butter, 1/8lb olive oil, 1-2 cloves of garlic, ~1/16t black pepper, no salt, no sugar, 1/2t parsley, basil, oregano. mince garlic, add 1T of olive oil to a saucepan. brown your garlic. add the spices, butter and margarine and turn down to a low heat until melted, stirring as needed to prevent sticking. when it's all melted, stir/whisk in your remaining oil.
why oil? it keeps the butter fluid at room temp enough to be used without a knife, but still thick enough to stick to a silicone brush.
if i'm making a garlic ranch base, i use hidden valley ranch powder 1T to 1/8c light mayo (not miracle whip) and 1/2c 2% or whole milk (not heated at all at any point) to a cooled garlic butter mixture at a ratio of garlic:ranch 2:1 to 4:1 depending on the toppings.