Got the wrong girl's attention in a cafe

Hey guys,

So, I'm visiting friends at the beach, and since they work, I go out solo during the day for lunch and chatting with people, etc.

At a nearby super-busy cafe, one of the waitresses had me picking my jaw up off the floor (I hadn't seen her there the last time I had lunch, so wasn't expecting a just-my-type petite brunette HB9 behind the counter). We made eye contact and held it for longer than accidental, but when I got to the counter, I was helped by a different girl (who is cute, but not my type, maybe an HB6), and the HB9 was in back putting in orders. So, I was kinda unsure what to do and just placed my order; but I guess I was still giving off an "interested" vibe, as the girl who took my order was totally into me (which is rare enough when I'm not trying that I didn't know what to do with it, so I AFC'ed and didn't do anything with it).

Anyway, I sat down where I could see HB9 in the full-wall mirror, and waited for my food. HB6 delivered the food with enthusiasm and a super friendly expectant smile, and I was still too focused on HB9 (and had forgotten that I'd caught HB6's eye) to make conversation or anything. So, you're already thinking, "Man, this guy is helpless...obviously you make friends with HB6 and she'll introduce to HB9 later.". But, it gets worse.

HB6 comes back later (this is not that kind of restaurant; you order at counter, they bring your food, you eat, you throw your papers away, you leave), after inventing an excuse (the fries were too crispy, so she brought me another order). I'm caught off-guard by this, too, and just say, "Thank you." a little too enthusiastically.

So, I'd like to try again with this HB9 before I leave the area. What the heck do I do with this? Obviously, I don't want to be the creeper that hangs out staring at HB9 in the mirror.

Ideally, I'd just walk in next time, and HB9 would be at the counter, and I'd chat her up some before ordering, and then later when she brings out my food, and then a final time while dropping a tip in the tip jar, while hopefully making enough progress to get a number or a "hey let's meet up tonight". But, this place is busy, there are four or five girls working during lunch...and there's always a long line, so I can't really hang out at the counter making chitchat without being the asshole holding up the line.

Any advice for dealing with an environment like this? I though about "bumping into her" at closing time...but that seems problematic (dark, cold, she'll be tired and focused on getting home and out of the cold, etc.).

Should I, instead, be hoping that HB6 is around tomorrow and I can shoot the Sh1t with her, since I'm pretty sure she's gonna be a friendly target? I dunno how to turn that into an intro in a busy working environment like this. Maybe I go later and hope for less of a crowd?