I used that same amount. that was when I got the 1/2 inch vellus hair on areas that were slick bald for years. No side effects either. I just stopped to go in for surgery.
I really think 3-4x per day is much better than 4mL 2x per day like I did.
As the foam, my brother used it. He said it was wet for maybe 30 minutes, but usually dried in 10. He used it 3 or 4 months while on the RU. I bet his shed was from the foam. He just gave up and won't use anything now. I talked him into getting fincar though and just using that.
I was applying rogaine everywhere on my head... hairline... sideburns... crown..."EVERYwhere" even where there was no balding. I was applying 3-4 times a day to the point where my head was soaked with liquid Rogaine. If anyone has that movie "Failure to Launch" watch the beginning and you'll see me 6 months on rogaine in it and see what my hair looked like. It looked better then I've ever had it. My hands for some reason looked like hell tho... they were getting wicked dry and flakes were all over them.
After I got off Rogaine I lost all that hair in about 2 months and was shedding like crazy. I got on alot of supplements for hairloss which did nothing... and people started commenting that I looked like I was going bald again.