The trick with reverse bookings is to see where the "default" settings are set - for those WG's that don't change the defaults when searching. The default hourly rate is set to £75 per hour. So putting a bid on for 2 hours for £150 should catch everyone looking. A 2 hour rate for less than £150 will only catch girls that change the "default" to a lower hourly rate. Some girls know to do this, others don't know they can. You can also use decimal points for the hours required - eg 2.4 hours = £180. I have done some really tongue in cheek rates to see what the response would be - and have enjoyed some cracking bookings as a result - plus repeat ones at the same rate when they know you are an okay guy. Some girls, especially outcall only ones, live on RB's as they can plan their week and usually will do the "deal" well below their normal rates. If the going rate in an area is £150 an hour then don't put that as your RB Rate for gods sake! - the idea is to get a good deal as it should be a reliable booking for the girl, rather than a time waster. How low do you go? - now there's the question! Girls that do overnights will change the default rate to much lower as 12 hours at £100 would be alot of cash otherwise - these are the ones you can catch on a short booking for a lower than default rate.
The default date setting is 7 days - so monday to monday etc., To maximise the bids, place the RB 7 days ahead.