I have a tip for you. Try this.
In the mornings, shower and then wait for your hair to completely dry. After it has dried, go ahead and style it. Wait for the hairspray to dry (10 mins) and then do your minoxidil application.
BUT, do NOT do the standard corn rows application. First off, this tip only works with the dropper applicator, not the dauber. So, if you have a dropper, take the dropper and after sucking in 1ml, wipe dry the sides of the dropper. With the dropper, 'poke' it into your hair, past the dry styled hair until it touches your scalp and then let out a little droplet.
Continue to do this over your entire head, 'dotting' your scalp with droplets of minoxidil spread out over the affected area.
Of course, this only works if you style your hair with a 'dry' look. If you are a gel guy, or a wet look guy, then this probably won't work because the scalp will have a nice coat of impenetrable gel on it.
I got this tip from Cassin, and it works fabulously for me. Sure, it still occasionally drips down my forehead which is why you should have a tissue in your hand while you apply it, but it keeps the sh*t OFF of your hair, and 'pokes' it through your hair so any greasiness is only on your scalp and not in the hair over it.