For a cash game, typically you set a minimum and maximum buy-in amount. At any time between hands if a player's stack is below the maximum they can purchase more chips up to the maximum. This is most commonly when you go bust, but if you're sitting on $2.15 after losing a hand you might wanna just get back to $10 instead of playing a tiny stack.While I understand the meaning of Buy-ins, it's something I haven't researched, yet, in how that mechanic works in a £10 cash game. I fully admit I should do this before ordering any chips (!!!) so that may well be tonight's exercise. When people can do it. How they re-buy in to the game. I'm sure all that is on this forum somewhere.
Trying to put you in the shoes of my neighbours - as said this is a social affair as none of us play poker - I reckon the odd person(s) after the big blind will limp in with 10c, hoping for the blinds to call. And I think that'll happen A LOT at the beginning. Hence why I'm leaning toward more chips is MOAR as they will feel they can stick in the game for a bit. I want it to be fun over anything else. I want them to come back and play again!
So I get you - I really do - but I wonder if your friends are pretty damned good and know how to play, and don't mind looking down at only 18 chips in their stack, .whereas my neighbours would be "Is that all I get for ten bloody quid?"
I'm going to learn a LOT after the first poker night, that's for sure. I can't really visualise how things will go. Cue me coming back here in a few months apologising to you! But I'll bear what you said in mind for the second or third game if our limp-fest turns into one game being two hours+ long.
I try to hand out all the small denomination chips with peoples initial buy-ins, and then when people want to top up or rebuy give them $1s or $5s and have them make change with other players.