who feeds who in ppc?

I have accounts with the top 12 ppcs. Bids are low on the smaller ppc engines so I can afford to place the top bids.

What I'd like to know, is, should I be aiming for the top position on findwhat and overture? Which search engines (i.e. google and the like) are fed findwhat and overture results?

If I am rank 3, rank 5 or rank 8, does this mean I am unlikely to be in the top 50 in google? Obviously it would be nice to be no.1 in the SERPS for all of my keywords, but the top 5 or 10 would be an excellent start. Any ideas on how high I should be bidding?

ALSO: I have noticed quite a decline in my daily spend on many of the bigger ppcs. I have not changed my ads or my bids and my ranking has stayed the same. This leads me to believe it's just a dip in the market, people perhaps aren't searching so much for my keywords at the end of the month. I don't want to just up my findwhat bids to get my daily spend up, but was wondering on how much fluctuation others see. It's only recently that I've monitored it so closely, and much of this is new to us!

Thanks SEO genius people!