Your right i dont...which is why i asked for advice on the subject, Being from UK yourself what is your plan with your sterling? Are you changing half Peso Half dollar or what? I would prefer to know so i am not getting stung on exchange rate.
The problem is, you're thinking waaaaaaay too much about this. Just tip early and call it good. If it's the same bartender the next day, tip again so he remembers. Just tip the guys, don't be stingy trying to only tip $20 for an entire week. You're better than this.
There is a thread titled "Tipping", you will find the answers to most (if not all) of your questions there. Tipping is new to me, with the exception of dining out, so I found this very useful.
No more than 100 dollars can be accepted for a transaction that is more than 100 dollars. Use pesos. Tipping in dollars is great because the wait staff etc. can go to Walmart, etc. and get the best exchange rate around to buy stuff. You too. Use small bills, 5s, 10s and 20s. Canadian dollars and other currencies aren't a problem. The new exchange laws try to combat money laundering and the drug trade, recognizing that drug deals are made in US dollars, not Canadian or deutche marks for that matter.
