A good field report dude.
I love the rush opening sets give me, and as you said when you come back from opening sets and your friends are in awe at your confidence.. thats quite a feeling
In regards to opening sets, what I tend to do is this.. (i know its a little text book, but it works).
1) whist walking make eye contact with a member of the group before/during when you walk past.
2) go straight in for the opener. just as you did in your field report, opinion openers are perfect for large sets.
3) whilst your talking to them, grab a spare chair thats within reaching distance (if theres one round), swing it round and sit down. hopefully at the head of the table. (i find this place is usually free and instantly makes you centre of attention.)
i've never had any success when talking to a seated set when standing up. i've never felt part of the group when standing and they're sitting. and if you're not feeling it... neither are they.
4) just before you give the opener, I always go with something like "hey, quick question guys, before i grab a drink..."
5) whilst i give my opener, 1/2 way through i tend to spontaneously say "hey! wicked hat btw.." and carry straight on with my story. shows your spontaneous, confident and you then don't appear too intimidating.
Then when you want to leave you can go with "right thanks guys, im gonna go grab my drink! ... anyone else coming to the bar?" and if you deliver that line looking at your target, majority of times she'll join you.
Which is essentially what you described, minus the time constraint?
I believe it was you who was saying your style is similar to mine? cocky/fun/playful/confident? .. If so, if I can pull it off i'm sure you won't have any problems next time.
When you do the apocalypse... I want field reports!! I'm gonna try that in london this weekend with Wheeler, so i'll post back.