Forever. Those collectors halt drydown in the lower half or two-thirds of the windrow. Swathing it as wide as possible out the back of the mowers gives the fastest, most consistent drydown, which is critical for retaining the carbohydrates in the plant; collected up like this the plants remain alive for hours or even days under certain conditions, and normal respiration burns up most of the carbs during that time. The only way the collectors make any sense whatsoever is if the crop is going to be harvested at really high moisture, which is usually bad for crop quality (clostridia bacteria dominate fermentation at really high moisture, which makes the crop slimy and often has excessive levels of butyric acid which is extremely undesirable.) The only way to make this work is to inoculate and / or acid treat at harvest at very high concentrations.

bluegtturbo way too low

I take it you have never run a mower round the outside of a feild here