Bell siphons are easy as pie. Check my greenhouse build and you'll see. My 1" standpipe with the 2" cap drains at around 20 GPM with a 6" drop. It kicks with flow rates as low as .5 GPM. The key is to slope the drain pipe up just a bit so that it is full before the system starts to drain. With a 1" drain going to a 2" common pipe it only needs to slope up about 1" from the low point.