BTW, how much 'mileage' can I expect to get out of $100 worth of Adwords credit? Is it even worth bothering with?
Thanks!
Adsense was seven years in the future
That (and other) threads are not all about what I said. I just pointed you (and joked a bit) to what I think you should be aware of, just in case.
By digging more, I'm sure you'll find peers that got into trouble - AW or AS. Not all, but some for sure, and they all made a claim about how good their site was, and how it still ranks high in organic results.
So, just be aware, and then decide what to do.
In regards of your specific questions, as you've mentioned, every situation is different.
Choosing keywords - you know what you're after, right? If want careful approach, use exact match at the beginning.
Setting budget - Tough call as some keywords may be in a range over $3, even $6 or $10 while other in range of 10 cents. Depends on industry.
Bidding option - if aggressive, get most of clicks, if want to spread, pick the other one.