Prepaying credit card charges

I’m carrying a credit card balance that I’m slowly paying off.

That same credit card is also where most of my bills go, including my annual vacation spending.

Here’s what I used to do before YNAB:

Let’s say my vacation costs about $1,200 per year.

Instead of saving it in cash, I would send $100/month directly to my credit card for 12 months.

Then when the $1,200 vacation charge hit the card, my balance would basically stay the same because I had already “pre-paid” it.

Now I’m trying to figure out how to handle this correctly in YNAB.

Do I assign $100/month directly to the Credit Card Payment category (since that’s what I’m physically doing), and then categorize the $1,200 charge as Vacation when it hits?

Or assign $100/month to a Vacation category, let it build up in checking, and then when the charge hits, categorize it as Vacation and pay it off immediately?

How do people usually handle this when they’re carrying a balance?