Sorry for the long delay in my response to your questions. If you've been reading my spread betting blog then you will know why I have been away.
Here is my response to your questions. Others can feel free to correct me or add to my answers.
1) Pro real time has back testing capabilities so you can use them if you like. Capital Spreads
also offer back testing facilities and if your reasonably computer savvy you can down load historical data from yahoo finance and add it into excel to back test. I know offthelip uses excel and yahoo so he might be able to help you more on that if your interested.
2) The prices are based on the underlying market but you are just betting on price movements. That's essentially what spread betting is, speculating so many £ per point on whether the price of the instrument will go up or down.
3) The FTSE 100 trades around the clock so 24 hours during the week and generally closes at 9pm on Friday and re-opens around 9pm on Sunday evening. Spread betting allows you to trade the FTSE out of hours but you will pay more in terms of spread for trading out of regular trading hours.
4) To be honest I can't really comment on this strategy either way it could work out well or it could empty your account quicker than you can sneeze. If you think it's worth a shot then that's your call. If you do try it out please do let us know how you get on.
Ok I think that answers everything, how I said if anyone else wants to pass comment please do so.
Again sorry for the delayed response, this is the usually rate of reply.
May the markets be with you!
The Spread betting beginner