I used this technique for my last contest and it works extremely well. I use an Ozark Trail Folding Cot, Mainstays Home Bed Extenders and 4 pieces of 2x4. The bed extenders come in a 4 pack, so just stack them so you have 2 pedestals for the foot. This will give you the correct foot height to achieve the 6 degree angle. If you take 2 2x4 blocks and stack them they are the perfect height for the center support. Then I just tape the pedestals to the foot, so the cot does not slide off. The angle is not bad enough to cause a headache or head rush. I guess if your BP was really high then it might, but I was fine and I have loaned it to some powerlifters who had to make weight and they didn't have any issues.
Anyways, doing this along with some water manipulation and the following diuretics: two shots of crown the night prior and 3 grams of vitamin C to start then 1 gram every 2 hours the day prior up until I cut off water, Weigh in was at 5 pm Friday and I woke up Saturday morning 13.1 lbs lighter. The lighter than my trial runs without the hold down tilt technique by 4 lbs.