Personally, I open the lid only about 1/2 way open, then push the autosiphon in until it hits the other side of the bucket. the angle will be pretty shallow as the lid is pushing down on the siphone. I start the siphon, then I keep on pushing, sliding the tip of the siphon down the opposite side of the bucket. when I hit the yeast, I see it pull through the siphon tube and I pull it back a bit. once you're at that level, you'll pull our all but about 2-3 oz of beer without getting more than 1/2 oz or so of trub.
for a carboy you're much better off with a carboy cap, a racking cane and a co2 bicycle tire inflator (or co2 from you're keg setup if that's convenient) Push the racking cane down the middle opening of the cap about 1/2 way. Use a 2-3" length of 3/8 ID tubing to connect the bike tire valve (the bigger kind, can't remember if that's presta or schrader) to the side opening of the cap. push the button on the co2 and it'll pump the beer through the racking cane. You're siphon's started and you can adjust the depth of the racking cane as nessecary.