Using a packet of dry Hidden Valley Ranch mix, changing the directions and then calling it your homemade ranch is totally okay. Because I say.
On the back of the above package the directions call for 1 cup of mayo and 1 cup of milk. I make it this way all the time for dressing and it is Num Yummy.
When I want a good thick dip for my mounds of celery and cucumbers that follow me polishing off around 15 wings or so I make it this way:
1 packet HV Ranch dressing/seasoning mix packet
1 cup mayo
1/2 cup sour cream
1/2 cup milk
You're already excited, I know.
The sour cream makes it a little more tangy and less milk makes it thicker so that more will stick to your veggies.
Because who wants to see any veggie showing through where you have just dipped?
Go make this.