After playing poker full time for a few years, I've change a lot of my ideas about gambling at pool. I was forced to treat gambling as a business, something I never really did much in pool.
I personally prefer having a set amount of money to be locked up and/or a time limit in place. I used to hate when I'd play someone for X amount of dollars per set, only to find out they would only loose 2 or 3 sets max when I was willing to lose much more. I had one instance where I lost 800 to someone one week and the next week they quit when they lost 300 and wouldn't play me with a fair game again. Obviously this was smart on their part, but I had no idea going into the first session this would be the case. After playing poker and knowing what kind of X dollars per hour I needed to make a living and having to choose only games where I could make this amount or more, I do the same thing in pool.
If someone wants to play 50 a set, I'd play races to 7(5 is ok, but I hate short races like that, too much variance) and have the stipulation we play until someone is ahead X amount and then decide whether or not to keep playing or play for X amount of hours. The reason I insist on locking up a certain amount is to make sure its worth my while before I start playing. In poker, if I see a table I know I can't make my hourly rate at, I don't play. In pool if I want the potential to make 200 in 8 hours or less and someone is unwilling to lock up 200, its not worth my time and I don't play.
The reason I always give someone a time limit on my playing is to avoid the stupid age old "don't quit while you're ahead" attitude of pool players.
For amounts around 1000$ or more, I prefer to play ahead sets as I feel that is the best test for proving the better player that day.