If you can cover the area then yes. Some ppls noggin is bigger than others I say.
Personally I use anywhere from 1ml to 1.5ml at night for my scalp as I have diffused thinning and a lot will get wasted in the hair.
I try to stick to the 1ml in the morning however.
Biggest thing to worry about though when using more than 1ml isnt so much the Minoxidil but the added amount of PPG and Alcohol can cause some inflammation of the scalp for those with sensitive skin.